user defined 3D Shape for flow item

I created own 3ds files. When I use this for flow items I can't change the color in the property editor. Also (the bigger problem) the color can't be changed during the simulation by triggers.

In addition, when I want change the 3D shape of the flow item by trigger, the flowitem get the new shape but the dimensions of the flow item (height, length, width) is not changed.
Is it a problem in Flexsim or is it only a problem with my shapes.
I created my shapes with different programs. Everytime the same problem.

You'll find in User Manual of FlexSim a chapter called "Preparing a 3D File" with a lot of useful informations:

Getting the Object's Color to Bleed Through
For .3ds and .ac files, you can have the FlexSim object's color bleed through on certain shapes in the file. You can do this in one of two ways: (1) give the shape an ambient color value of rgb: (0.235,0.235,0.243) in your 3D software, (2) append "_fsclr" to the end of the shape's material name in your 3D software.

If you change the shape of a flow item during simulation run the size of flow item doesn't change. This has to be done with setsize(item, x, y, z).

Greetings