A separate Isosurface plugin would be much better than forcing its creation with the 'raw script plugin'.

Isosurface_test_A_.zip 5kb
   Isosurface_test_A_.bsp 1.0.2.1a

Raw_script_plugin_testA.zip 5kb A slightly better version with some code clean up.
   Raw_script_plugin_testA.bsp 1.0.2.1a

Raw_script_plugin_testC.zip 8kb
   Raw_script_plugin_testC.bsp 1.0.2.1a

Some code cleanup, more comments, better contained_by statement, Ib_torus3 is a newer torus with major/minor radius.
Raw_script_plugin_testD.zip 9kb
   Raw_script_plugin_testD.bsp 1.0.2.1a

Start MegaPov first, then Bishop3d.
  Open Raw_script_plugin_Mechsim_test.bsp
  Settings/Modeller/Exporter/Animation/Export all selected frames at once
  Settings/Render/Animation Initial Frame 1, Final Frame 60
Render at 320 x 240

The script will create a file "Mechsim_test.dat", this containes the state of MechSim between frames.

Settings/Modeller/Exporter/Animation/Export all selected frames at once
Settings/Render/Animation Initial Frame 1, Final Frame 220
Render at 320 x 240

The script will create a file "Mechsim_test.dat", this containes the state of MechSim between frames.

Three point masses interacting with a bishop3d enviroment.

As part of a discussion on the Bishop3d forum

Object_shear_2.zip 6kb
   Object_shear_2.bsp 1.0.2.5b
   File contains:
      CSG of individually formed shapes, upper left
      CSG formed as a group, upper middle
      CSG of copied re-imported shape, to form new shape, lower middle