Animation Notes

The following information is new for Version 9.0:

The following information exists from previous releases:

Limitations Fixed

See the What's New for a complete list of animation enhancements.

Fixed Ellipse curves don't give correct render results when used as motion paths.

Fixed If the Local Parameters for the Perspective window are turned on in the Param Control window, the camera is selected, and when the local parameters for the Perspective window are turned off, Alias will crash.

Fixed Can't write SDL in batch mode for IK animation with construction history or blend surfaces.

Batch mode has been replaced by the openModel app AliasBatch.

Fixed The first time that the Skeleton editor is used with List Type > Handles and List Mode > Picked, the affected joints are not displayed in the Skeleton editor.

Fixed If you are grouping or ungrouping objects in the ASBD window, move the cursor outside of the window, and then let go of the mouse button, then you will appear to be stuck in rubber-band mode when you move the cursor over the ASBD window again.

Fixed Toggling the cluster percentage type may cause the geometry to be drawn incorrectly.

Fixed If an object has CVs with keyframed animation, and other CVs with expressions referencing the keyframed CVs, the keyframed CVs will not play back correctly.

Fixed Playblast does not work with image planes.

Fixed When using particles or Animation > Run dynamics, displacement mapped geometry wasn't always recognized

Even though an object is tessellated according to its displacement map, its bounding box was calculated from the original geometry. The bounding box is now expanded to cover the expected displacement mapped geometry.

New Limitations

Limitation

When creating geometry from a Symmetric Layer, animation and clusters are not copied.

Workaround

Do your cluster attachment after the real geometry has been created. If your symmetry plane is an axis plane, you may use Edit > Mirror to copy the geometry and animation.

Limitation

When using ungroup with Copy Node option, the new nodes get instances of any animation curves that were on the original nodes. If you then edit the original curves, the new branch is affected as well.

Workaround

If the above is NOT the desired behavior, cutting and pasting the curves in the action window will create new copies.

Limitation

The grid does not update during a Time Slider scrub when there is a constrained camera.

Workaround

Turn Optimization off in the Playback Options.

Limitation

Camera animation does not update during Quick render with Animation on.

Workaround

Use Playblast with the Quick Render option On.

Limitation

If you use Playblast, and Quick Render with Animation in the same session of Alias, window focus works incorrectly for the remainder of the session.

Once you have used both of the above features, then mouse clicks in the modelling windows are ignored until you invoke a tool from the menu or palette.

Workaround

Just use Playblast. Turn the playblast Quick Render toggle On or Off as needed.

New IK and Constraint Limitations

Limitation

UV constraints ignore displacment maps on surfaces.

Workaround

You can warp the surface instead for a similar sort of effect, and UV constraints do work with warped surfaces.

Limitation

Local axes behavior is not consistent if the local axes have not been explicitly set.

If an object has never had its local axes explicitly set, we assume that they are always at a (0,0,0) rotation in object space. So if you watched the local axes while you Zero-xformed the object, for example, the local axes would appear to be xformed as well. However, if you had set Local Axes, we do not modify them during Zero Xforms.

Certain operations do explicitly create Local Axes, for example: skeletons always have Local Axes; Edit > Duplicate Object creates explicit local Axes. Visually, there is no way to tell if there are explicit Local Axes there, or if we're just using the defaults, so certain tools will appear to behave inconsistently with local axes.

Workaround

Set your local axes explicitly to the desired orientation.

Limitation

Duplicate object does not remap constraints within the copied hierarchy.

Workaround

If both the constraint target and destination are in the copied hierarchy, delete the constraint and reapply it to the new objects in the new hierarchy.

Limitation

In the Objects > AddIKHandles option box, Reset does not reset all the options to their default values.

Workaround

Reset these options by hand: the default for Orientation is Local, and the default for SetRestPose is Off.

Limitation

An object with multiple aim constraints may not evaluate correctly.

Aim constraint rotations are restricted to -180/+ 180, however these restrictions were not enforced consistently throughout the weighting process, so if individual constraints caused rotation values of opposite sign, errors may result.

Workaround

Use a single object as the aim constraint target where possible. If you're really dependent on the animation of 2 separate targets, then point constraining an object partway between the original targets and using this new object may provide an adequate approximation.

Limitation

Query Edit will not display more than 10 constraints per object.

Workaround

If you see 10 constraints, check the info window to see if there are any additional constraints that you may have missed.

Limitation

IK skeletons in symmetric layers will not be mirrored to the other side of the axis of symmetry. IK skeletons use non-leaf dag nodes and clusters and these are unsupported in symmetric layers.

New Cluster Limitations

Limitation

Splitting a cluster where the members are present at the dag node level in the cluster editor may cause the geometry to be drawn incorrectly.

If the cluster members are all at the CV level, splitting works correctly. However, if you see an entry in the cluster editor for several surfaces, then some of the geometry will jump to the wrong location when the cluster is split.

The geometry is still there; it's just not redrawn correctly. It will reappear when the cluster transformations are applied again (for example, when the cluster is moved, rotated, etc.).

Workaround

Xform > Move the clusters by (r 0 0 0) to make the geometry redraw, or expand the cluster members down to their CVs before splitting.

Limitation

If polyset vertices are placed in a cluster, the vertices themselves will not be drawn when the cluster is picked.

Workaround

Unpick the cluster to see the vertices again.

New ASBD Limitations

Limitation

Anim sweep may produce dags which overlap others in the ASBD window.

Workaround

Close and reopen the ASBD, or switch to another ASBD layout and back, and it will be drawn correctly.

Limitation

If you are doing a Camera->lookat in a modeling window, and the option box is open and the Go button overlaps the ASBD, then the lookat will take place in the ASBD instead of the selected modeling window.

Workaround

Move the Option Box so that the Go button isn't sitting on top of the ASBD.

New Particles Limitation

Limitation

Particle collisions with deforming surfaces do not always work correctly.

Animated displacement maps may allow particles to go through the collision surface.

Warped surfaces with xforms above the surface do not collide correctly.

Workaround

For a surface with an animating displacement map, you may need to use additional forces to keep the particles away from the surface. For a warped surface, Doing an Edit > Zero Xforms will help.

Limitation

Particle Emission doesn't work correctly with symmetric nodes.

Symmetric nodes are just like instances, particles will only be emitted from one half of the symmetric pair. As well, the instance that emits is not the same one in the interactive as in the renderer.

Workaround

Create Geometry before doing particle emission.

Limitation

Particles don't display properly, when viewing in Construction Planes.

Workaround

Set up a camera to mimic the construction plane view.

General Animation Notes

Limitation

Linear Tangents may not work correctly for a Parameter curve with large values.

When the slope of the curve segment between 2 successive keyframes is greater than 573 - that is, tan(89.9 degrees), linear tangents are not calculated correctly. (We truncate the values to avoid numerical errors elsewhere.)

Workaround

Create the curve on a dummy node with a smaller range of values, and use an expression to scale the value of the curve.

Limitation

Playback of visibility animation may put invisible objects on the pick list.

If you pick an object with visibility animation at a frame where it is visible, play back and then stop playback at a frame where the object is not visible, then the object remains on the pick list, and may be inadvertently transformed or deleted.

Workaround

Use Pick > Nothing to ensure that there are no invisible objects picked.

Limitation

Viewframe and Playback do not update a static expression.

For example, if you set an object's X-translate channel to the constant expression "1", and then Xform > Move it away, it will not be reset to 1 by viewframe.

Workaround

Set a keyframe for these values instead, or use an expression like "1+ frame * 0" instead of a constant expression "1".

Limitation

Animation > Turntable does not rotate about the origin when grid snap is on.

If grid snap is on, Turntable ignores the Rotate About Origin setting (in the Turntable Options box, Animation > Turntable-), and rotates around the pivot point. If grid snap is turned off, and Turntable is selected again with the same options set, the primitive rotates around the origin.

Workaround

To avoid this problem, ensure that grid snap is turned off when invoking Turntable.

Limitation

CVs on any object with construction history cannot be animated using any of the animation tools (such as Animation > Set keyframe).

It is not possible to add keyframes to CVs on curves or surfaces with construction history, such as blend surface, skin, and path.

Workaround

To be able to animate CVs, pick the curve or surface and use Del > Constr history.

Limitation

Anim > Set motion with the FLOW option on only works on root dag nodes.

If a selected dag node has any transformations in dag nodes in the hierarchy above it before the Set motion operation was invoked with the FLOW option, then the selected dag node may not FLOW properly along the motion path.

Workaround

Ensure that the selected dag node is a root level dag node, or that no dag nodes grouped above the selected node have transformations. You can group the dag node and put transformations above the dag node that was FLOWed after the operation is complete.

Limitation

CVs from a motion path cannot be animated.

Workaround

You can achieve the same effect using spline control. Attach the geometry to a skeleton, put a spline handle on the skeleton, and animate the root handle position from 0 to 100. The curve and/or its CVs or any cluster containing its CVs may be animated as well.

Limitation

In Surfaces > Swept surfaces > Anim sweep-, the ABOVE mode does not work.

If an object is animated hierarchically, a non-root node is selected, and Anim sweep is invoked with hierarchy set to ABOVE, animations above the picked node are ignored. Similarly, if the mode is BOTH, and there is animation above, it will not be recognized.

Workaround

Copy the geometry, delete the other branches, and anim sweep from around the root node with hierarchy set to BELOW.

Limitation

The rand() and gauss() functions do not work correctly in expressions if there is any particle emission occurring.

Workaround

Turn off particle emission, bake the rand() and gauss() expressions, and then turn particles back on.

Limitation

Geometry doesn't show pivot when it is in simpdisp mode.

Simpdisp improves draw and cluster performance for surfaces. Because drawing pivots can be slow, they are not displayed for these surfaces.

Workaround

Toggle simpdisp off on the object to see its pivot.

Limitation

Copying CV animation from object to object doesn't work (Edit > Duplicate channels).

Workaround

Pick the dag nodes above each of the objects instead of the CVs themselves, select Edit > Duplicate channels-, and toggle Hierarchy Below on.

Limitation

Time warps are not applied to invisible objects in a hierarchy.

Workaround

Make sure that all the objects that you actually wish to timewarp in the hierarchy are visible.

Limitation

Making objects visible after a viewframe or playback does not automatically update those objects to the current frame.

During playback or viewframe, we do not calculate the animation for invisible objects. If these objects are subsequently made visible, their state will not by synced up to the current frame. Note that cluster transforms are re-applied when an object is made visible, so that cluster animation will be in sync (if the clusters are visible at the time).

Workaround

Do a viewframe with the desired objects visible.

Limitation

Retrieve Anim may cause an expression to reference an existing curve rather than a new curve if in the Anim SDL file the expression refers to a Parameter curve that has the same name as a different curve already present in the model.

Workaround

Either rename the existing curve before retrieving the animation, or edit the Anim SDL file and rename both the curve and the expression's reference to it.

Limitation

Retrieve Anim with Overwrite Names OFF may result in expressions referring to non-existent parameter curves and give a syntax error with no further explanation of the problem.

Workaround

Use Overwrite Names ON in the retrieve operation, or rename the existing curve or the curve in the Anim SDL file prior to retrieving.

Limitation

The Animation > Playback options-Playblast window does not respond to mouse events.

When playblasting an animation, the Playblast window that is displayed does not respond to mouse events.

Limitation

Animating an image plane sequence can sometimes cause single- pixel vertical shifts.

In the interactive package, animating an image plane sequence can sometimes cause single-pixel vertical shifts of the Image Plane in the Perspective window during playback if the following conditions are present: the camera field of view and the size of the Perspective window are not even multiples of the image plane's resolution. ("Single-pixel" in this case refers to a pixel of the source pix file, and not a screen pixel.)

Workaround

Try to make the size of the Perspective window an even multiple of the resolution of the image plane pix files.

Limitation

Image planes will not load using either File > New image plane or the Add button in Windows > Camera editor if their names have alphabetic characters in a numeric extension.

Image planes require an animation sequence that is defined by numeric digits in the extension, and cannot load when alphabetic characters exist in the extension.

Workaround

Ensure that the names for any pix files used for loading image planes so that only digits appear after the extension. If there is a field-rendered sequence with image planes, use "filace" to paste the odd and even images together.

Limitation

Padding frame extension names by 5 or more digits causes problems on file textures.

Workaround

Limit padding to 4 zeros or less.

Limitation

The screen sometimes flashes when retrieving image planes that were stored in RGB mode.

Workaround

The flashing will not affect the retrieval of image planes, and can be ignored.

Limitation

Image planes and associated animations are not retrieved correctly if referenced pix files cannot be found.

Workaround

Ensure that all referenced pix files associated with an image plane are in place when you save the wire file. If necessary, use a placeholder pix file when saving out the wirefile. If this is not done, the animation associated with the image plane may not be retrievable.

Limitation

Creating and Copying light animation may be confusing.

Workaround

There are different ways of picking lights for animation, depending on which parameters you want to animate.

To animate a light's transformations (translation, rotation, scale) or visibility, pick the light in a modeling window or pick the appropriate light dag node in the SBD window.

To animate any other light parameter, such as color, intensity, or glow, pick the light in the Multi-lister window. When animating a light through the Multi-lister, the light should not be active in the modeling window unless its transformations or visibility are also to be animated.

To copy all light animation from one light to another, select the root node of one light, and use Edit > Duplicate channels - with Hierarchy set to BELOW and Parameters set to ALL in the Duplicate Channels Options box. The animation of individual light (or shader, or texture) parameters can be copied by selecting the source light in the Multi-lister, doing a Shift-select of the light to be copied to in the Multi-lister, and then Shift-selecting the desired parameters in the light (or shade, or texture) editor. Invoking Edit > Copy Parameters in the Multi-lister will then copy the animation for that parameter.

Limitation

Face-surface CVs can be included in clusters and animated, but will not render properly if they are not maintained in the same plane.

Workaround

Limit transformations of face-surface CVs and clustered face- surface CVs along the plane of the face-surface.

Limitation

Shapeshifter yields incorrect deformations with influenced base object.

Workaround

Always return the shapeshifter base object to its neutral, undeformed position before creating the next shapeshifter target pose. You may also re-order the clusters in the cluster editor so that the new shape-shifter clusters appear before any existing clusters on the object.

Limitation

Reload Active doesn't work on a flipbook that has been unloaded.

In flipbook, if you use the Book Management menu to Unload Active on a book, subsequent attempts to Reload Active on that book will fail.

Workaround

Use the Delete Active function to get rid of the book altogether, then load it back in using New Book.

Limitation

On some graphics systems, dithering occurs when flipbook is started up when Flipbook > Options > Dbl Buffered is turned ON.

Workaround

While flipbook is running, close it and turn Dbl Buffered off.

IK and Constraint Limitations

Limitation

If the joint angle animation output for Single Chain IK jumps from
-180 or 180 degrees (or from 180 to -180 degrees) from one frame to the next, motion blur will not work properly.

Workaround

Use the motion blur compensation option in Run IK. This will insert additional keyframes at the motion blur sample points near the jumps.

Limitation

Multi-chain IK animation must be run from the same initial state to get the same animation.

To perform RunIK when multi-chain handles are present, the skeleton must be in a known starting position. If you select Assume Rest Pose before doing RunIK and make sure that you are at the Start Frame, the same animation is generated.

Workaround

If you want to render only a subset of the frames in your animation, you must still follow the above steps and run IK for the whole range of animation.

Limitation

The joints between two aligned bones tend to "lock up" in IK animation.

If two successive bones in a hierarchy (for example, a thigh and calf bone) are in a straight line, they may not bend even when a constraint on the lowest joint (the ankle) has moved. This occurs because reaching the ankle constraint would need to bend both at the hip and knee, and neither joint wants to move without knowing the other will also move. Otherwise, the ankle would be temporarily too far from its constraint.

Workaround

To solve this problem for a multi-chain handle, set up joint limits (in the above case, on the knee joint) so that the two limbs can never be in a straight line (2 or 3 degrees from straight should be sufficient). For single-chain, the solution is to set up the rest position so that the joints are not aligned in world space.

Limitation

When saving out an SDL file, IK and constraint animation is written only for the range of keyframes specified in the Render globals window.

This means if you edit the start/end frames in that SDL file, you won't have the constraint/IK animation outside the original start/end range.

Workaround

You must re-save the SDL in order to get any missing constraint/IK animation.

Limitation

World orientation does not work on a Single Chain handle with non- proportional scale.

If the root joint of a Single Chain handle inherits a non-proportional scale, Worldspace Orientation for the plane will not work correctly.

Limitation

Zero Transforms may cause problems with IK models.

Using Zero Transforms on a skeleton with Attached Geometry present will cause the geometry to be displaced. Using Zero Transforms on a skeleton with Single Chain Handles may cause the joints to rotate if the handles are animated or constrained.

Workaround

Detach geometry, and remove or disable handles before modifying the skeleton.

Limitation

The Modify operation in the Character Builder does not work correctly if the Skeleton hierarchy has been used in multiple Attach operations, or if the hierarchy to be modified encompasses a larger hierarchy than was used in Attach.

Workaround

In Windows > Deformation Control, perform the Modify operation on only one part of the skeleton at a time if all of the following conditions exist:
  • You use Frame Control > Attach with the Hierarchy option set on the upper part of the skeleton
  • You then perform another Frame Control > Attach with Hierarchy set on the lower part of a skeleton
  • At least one joint belongs to both hierarchies.

Limitation

In multichain IK, orientation vs. position weight varies with skeleton size.

If a skeleton has both orientation and position multi-IK handles on it, and it is impossible to satisfy all IK handle goals simultaneously, you may notice that as the skeleton is scaled, the balance between the effects of the orientation and the position goals may vary.

Workaround

Two simple workarounds are (a) set the scale of your skeleton before beginning, and do not animate the scale, or (b) ensure that all position and orientation goals can be met at all times.

A third option is to make separate multi-IK handles for the position and orientation goals. You can then animate the weights of the IK handles, while the scale of the skeleton is animated. This lets you control the balance between which of the goals should be satisfied more stringently than others.

Limitation

Scaling a skeletal chain with an IK handle may cause the skeleton to respond incorrectly.

Workaround

If you need to scale a skeleton or IK chain, turn off the IK handles, scale the skeleton and turn the IK handles back on. If you scale the chain with a non-proportional scale, you should delete the IK handle and then reapply it.

Limitation

If you have spline IK and single Chain IK, and a heavily clustered model, and the Spline IK is controlled by a clustered spline, this may cause write SDL to take a long time.

Workaround

Run-IK on the spline chains only, and disable the spline handles. Then render or write SDL (performance for the single chain WriteSDL should be adequate.)

Limitation

If playback is inconsistent or not render matching, then a model may have constraints or expression animation on joints that are affected by IK and it will be necessary to increase the evaluations-per-update in the Performance Options to get the correct solution.

Workaround

If you have a constraint referencing an IK joint, increase the Evaluation/Update (E/U) to 2. If you have a constraint referencing an IK joint whose handle has a constraint referencing an IK joint, increase the E/U to 3, etc. The reason that we made this a performance option is that you get a small performance hit with each added evaluation, so they should not be done unless necessary.

Limitation

The spline handle solver generates a solution in the range (-180 degree, +180 degree) for each of its joints.

This may result in problems when rendering with motion blur, or rendering on fields, as the interpolation will not be correct if the solution jumps from one end of the range to the other between two frames.

Workaround

Use Run IK with the Motion Blur and/or Field compensation options. You must disable the handles after RunIK, or you will not get the desired animation written out to the SDL.

Note that a Spline Handle is always constrained, so that if it's turned on it will solve and override any animation on the skeleton.

Limitation

Cumulative rotations of more than 360 degrees with spline handles may cause geometry to flip.

Workaround

Use the Anti Flip Controls on the Root Handle in the Information window to find a setting which keeps the rotations coherent.

Limitation

The root joint of a single chain IK chain may not be used as an orientation constraint.

The local axes of the root joint of the single chain IK chain are defined to be above its rotation. Constraints look at local axes, so that in this case the orientation will ignore the rotations on that particular joint.

Workaround

Use an expression to get at the rotation of the root joint itself.

Limitation

Joint limits do not respect the user's choice of units.

Translation limits are always in centimeters, and rotation limits are always in degrees.

Workaround

Convert the values you want to centimeters and degrees.

Limitation

If an aim constraint is in a configuration where the "forward" is exactly parallel with the "up" direction, there is no unique solution, and the constraint is not applied.

Workaround

Set a keyframe at the offending frame to force the orientation of the constraining object to be very slightly away from the problem value.

Limitation

Rendering with motion blur is erratic with animated constraints without IK.

The constraint solver generates a solution in the range (-180 degrees, +180 degrees) for aim and orientation constraints.

If you are using animated constraints without IK, this may result in problems when rendering with motion blur, or rendering on fields, as the interpolation will not be correct if the solution jumps from one end of the range to the other between two frames.

Workaround

Use Bake with Motion Blur Compensation to create keyframes for the constraint. This will create extra keyframes at sample points where needed. The sample points are at the frame, plus/minus the following value: 


(RenderByFrame * ShutterAngle) / 720

Limitation

The effects of invisible constraints are inconsistent. A constraint to an invisible object is not evaluated during playback, but is enforced during transformation of the constrained object.

Workaround

Use Edit > Constraints On/Off to enable/disable constraint updates instead of visibility.

Cluster Limitations

Limitation

Xform > Local > Set pivot of deformation clusters changes the object if there are percentage effect parameters set.

When moving the pivot point on a cluster that has some members' percentage effect parameter set to a value other than 100%, if the cluster has already been transformed with rotations or scaling, transforming the pivot point of the cluster will cause these cluster members to move. (The percentage effects are recalculated for each control vertex according to the new pivot point location.)

This behavior is apparent when clusters are created using the Deformation Control window (Windows > Deformation cntrl).

Workaround

Define and verify pivot point locations for deformation clusters before assigning transformations such as rotate or scale.

Limitation

Copying a cluster with Edit > Duplicate object creates a null node.

Workaround

Create a new cluster and empty it. Use the cluster editor to copy the cuts from the original cluster into a new cluster. This will preserve the cluster percentages. Reorder the clusters so that the new cluster immediately follows the original.

Limitation

Copying cluster members with Edit > Duplicate object places the new objects in the same clusters as the original, it will not create new clusters.

Workaround

Use Edit > Copy and Edit > Paste to create a copy of both clusters and members.

ASBD

Limitation

Clusters are not properly highlighted in the ASBD window when picking during or immediately after the transformation actions.

Workaround

Verify that the correct objects are picked in the Modeling window or in the SBD window.

Limitation

When using Xform > Move to change the layout of objects in freeform mode, picking an object that has construction history will bring up the warning message that construction history will be lost, and asks if you want to continue.

Workaround

Answer No, and then move the object anyway. (The message only comes up on the replace pick, and the object remains picked after you say no. You may safely pick the moved object in the ASBD thereafter.)

Action Window

Limitation

Using Edit > Cut in the window invoked from Animation > Action limits the undo function.

If you use Edit > Cut and cut more than one action on the same channel in the Action window, Edit > Undo may not work.

Workaround

Cut one action followed by the second action, or cut the channel as one item.

Limitation

The Action window's Edit > Paste segment and Edit > Paste keyframes change the character of original and pasted curves.

Pasting does not preserve the shape of the copied segment, and also alters the transitions of regions surrounding the insert location.

Workaround

Paste segment inserts keyframes at the insert location. If these keyframes have tangent identities associated with them, those tangent identities (for example, Tangent Type > Smooth) are preserved and are recalculated after the paste has been done.

Smooth tangents are especially sensitive to the location of both the previous keyframe and the following keyframe.

In order to both preserve the shape of the copied segment, as well as to preserve the transitions around the insert region, use the following workflow.

To copy the segment of an animation from keyframes 20 to 30, and insert it at 45 (between keyframes 40 and 50):

1
Pick the keyframes at 20 and 30.
2
Make the keyframes fixed ( Tangent Type > Fixed).
Tip: If you later want to restore their identity, you can use Edit > Undo.
3
Select Edit > Paste keyframes.
4
At this point you can use Edit > Undo to restore the original tangents.
5
Pick the keyframes at 40 and 50.
6
Make those keyframes fixed (Tangent Type > Fixed).
7
Pick the curve in the lister area.
8
Select Edit > Paste keyframes and insert the segment at 45.
>
Note: Steps 5 and 6 are only necessary if the keyframes at 40 and 50 are smooth - other tangent types preserve their identities.

Limitation

Sometimes the wrong parameters for a texture may be listed in the parameter control window or the Action window. For example, amult and aoffset may be listed instead of Rgbmult and Rgboffset.

Workaround

Select the texture in the Multi-lister and ensure the Texture Editor is open.

Limitation

Deleting instanced animation curves in the Action Editor is awkward.

Workaround

To delete only some of the instances in an object with internally instanced channels (for example, where the X translation of sphere#1 is instanced to sphere#2's Y translation and is also instanced to its Z translation), select ParamFilter in the Action Editor to turn the channels OFF to keep and cut or clear the other instanced channels.

Limitation

If more that one shader/texture/light with the same attributes is visible in the Action Window, Edit > Cut and Edit > Paste will not work properly on the attributes that appear multiple times, and Edit > Undo may not work for these items.

Workaround

Select only one item at a time in the Multi-Lister when editing in the Action Window.

Dynamics

Limitation

When using Animation > Run dynamics, if there is a scale transformation up the dag hierarchy from a dynamic object and the dynamic object is rotating dynamically, the scales may not be properly compensated for and the object may get stuck or move strangely.

Workaround

Run the dynamics simulation on the root node.

Limitation

When using Animation > Run dynamics, local links sometimes have no effect.

Workaround

When running a dynamics simulation, if any of the objects have locally linked forces (exclusively linked lights), the simulation must be run on the leaf nodes of the simulation in order for the local links to have any effect.

Limitation

The Active Environment shader collision wall conflicts with a coincident passive surface when using Animation > Run dynamics.

If a simulation set consists of an active object dropping onto a passive surface, and that surface is coincident with an active "Floor" collision wall (in the Environment shader), the object does not rebound off the surface, but instead comes to a dead stop.

Workaround

You can either turn off the "Floor" collision wall, or remove the Passive surface from the simulation to make the active object bounce.

Limitation

When using Animation > Run dynamics, dynamic objects that intersect at the beginning of a simulation may not behave correctly. For example, the objects may not move at all.

Workaround

Ensure that none of the objects in the dynamics simulation intersect.

Note that if the objects have BBOX collision on, the bounding boxes in their unrotated world space must not overlap. The world space bounding box may not be the same bounding box which results when Object Display > Tgl bounding box is used. A confirmation box is displayed warning you that objects are initially in collision.

Tip: The objects must be a small tolerance apart. Also, objects may appear to be apart, even when their tessellated geometry still intersects. If you want objects to intersect, group them.

Limitation

Instanced geometry does not work with Animation > Run dynamics.

Workaround

Dynamics simulations will not operate on instanced dag nodes, because they do not have their own geometry or their own dynamics properties. Ensure that dynamics simulations are always run on non-instanced objects.

Particles

Limitation

Hair cannot be split using Animation > Run dynamics.

If particles are of the type HAIR, Split is ON, and any force is applied to the hair, the segments will start to come apart.

Workaround

To avoid this situation, do not use the SPLIT Hit Method option when the particle motion type is HAIR.

Limitation

Confusion with particles emitted as checker pattern (Animation > Run dynamics; Windows > Multi-lister-particles, checker texture).

When the checker texture is mapped to parameters that use the alpha channel of the texture (for example, they are not colored), then the color1 and color2 parameters are ignored.

Workaround

To set the relative intensity of the checks for alpha mappings you must use the Contrast or the alpha amult and aoffset parameters. Among the alpha mappings are: Bump, Displacement, Reflectivity, Particles per second, Particle Speed, and Hair Length Map.

Limitation

The particle drawing approach makes collisions look incorrect when using Animation > Run dynamics.

The drawing of particles in the modeler may make particles in collision appear as if they had not collided, and that their motion is in the wrong direction. This is because particles are drawn as lines between the beginning and the end of each time step. If a collision occurred inside the time step which caused the particle to change direction, it is not reflected in the line drawn between the start and end of the timestep.

Workaround

To get a more accurate representation of particle motion, increase the By value in the Animation > Run dynamics window.

Limitation

The particle system size alters particle speed for SOLID or HAIR Motion Types.

The speed of a particle is related to the mass and the size of the particle, so that if the particle size is changed, the particle will move faster. The size of the particle is also used for rendering. Therefore, if particles are made to appear larger, their behavior is also affected.

Workaround

To control this behavior, change the particle size to get the desired rendered size, and then alter other particle parameters such as mass or speed to change particle speed.

Limitation

Particle run-up for Anim > View frame prevents you from resuming Animation > Run dynamics.

If a dynamics simulation is run, paused, and then viewed using Anim > View frame or Animation > Playback (which would cause a particle run-up to occur), the next time Animation > Run dynamics is used to view the simulation, it will start from the beginning, instead of continuing on from where it was paused.

Workaround

To avoid this problem, continue Run dynamics simulations right to the end, or avoid using View frame or Playback when a simulation is interrupted and will be continued later. Another solution is to toggle particles OFF (Display > Tgl particles).

Limitation

When using the renderer, objects or particle emitters whose visibility is animated cannot be incorporated into a dynamics simulation if they are not visible at the first frame.

Workaround

If an object is a particle emitter, or an object is used in a dynamics simulation, or serves as an object for collisions, and its visibility is animated, ensure that its visibility is ON in the first frame of a dynamics simulation, or at the start frame for particle emission before rendering the animation. When animating the visibility of an object that particles will collide with, run the simulation in pieces, stopping and restarting whenever the visibility changes. The particle files are then saved for rendering.

Limitation

Particles are not updated on those frames that are not actually displayed with Animation > Playback.

If you set a frame rate that causes the playback to drop frames, then particles will not be updated on those frames, and lag further and further behind the rest of the animation.

Workaround

Use Playblast to see the particles at a synced rate.

Limitation

Particle emission from a light may appear incorrect when using Animation > Playback if any of the light nodes are animated.

Workaround

Ensure that the lights are not optimized during playback by checking the setting in the Optimization Options section of the Animation > Playback options window.

Limitation

Toggling particle display with the option box open will not toggle particles OFF. (It will toggle them ON just fine though.)

Workaround

Toggle again without opening the option box.

Limitation

If you use Run Dynamics to save particle files, and the start frame is NOT the same as the Emission start frame, the particles saved will not be the same as in playback, since Run Dynamics does NOT do particle runup.

Workaround

Set the start frame to include the runup time, and then delete the unneeded particle files afterwards. To determine the runup time, use the Emission start time, or the Start frame minus the Max particle life span, whichever is later.

For V9 and later, Playback Options allows you to save particle files directly from playback. In this case, the runup particles are included correctly.

Limitation

Instancing particle emitters leads to different behavior in the interactive preview as compared to the final render. This applies to symmetric geometry as well.

Workaround

Create copies, not instances.



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