3dsMax scripting question

[kosso_olli]

Hey guys,
does anyone know a script that does the following:

- take all the materials assigned to a scene
- for each material, select the objects that have that material assigned
- collapse them into a single mesh

I tried my best to get something out of ChatGPT and the likes, but I only get some kind of pseudo-code.

Sadly my knowledge of MaxScript is so bad I don't even know where to start from.

[rusteberg]

I believe sini scripts has the ability to do that. Combine by material… I haven’t used it in a while but remember collapsing revit models into material groups that way. Which at the time was worth its weight in gold.

[hermit.crab]

Try this:

allMat = for m in scenematerials collect m
for i=1 to allMat.count do (
select (for j in objects where (j.material == allMat[i]) collect j)
collapse.setDoBool false
collapse.setOutputType #Mesh
collapse.setCollapseTo #Single
collapse.doCollapse $
)​

[kosso_olli]

Thanks for the help!
Unfortunately, I can not get this code to work as expected.
Attached you will find a scene with some objects and 4 materials. When I run the code, some teapots will dissappear, but no objects are collapsed.

mat_collapse.zip

[hermit.crab]

Works fine on my end. Check the attached gif. Have I misunderstood you?

[kosso_olli]

Hi Aleksandar,
on your end it is working as expected indeed!
Will try again, maybe I did something wrong.

[kosso_olli]

Well,
it is weird. On my end, nothing happens. But the listener is listing some errors:

#(01 - Default:Physical_Material, 02 - Default:Physical_Material, 04 - Default:Physical_Material, 03 - Default:Physical_Material)
-- Error occurred in anonymous codeblock; filename: ; position: 256; line: 8
-- Type error: Call needs function or class, got: OK
-- MAXScript callstack:
--    thread data: threadID:43856
--    ------------------------------------------------------
--    [stack level: 0]
--    In i loop; filename: ; position: 257; line: 8
--        Parameters:
--            i: 1
--        Locals:
--            i: 1
--            ​: undefined
--        Externals:
--            owner: undefined
--    ------------------------------------------------------
--    [stack level: 1]
--    called from top-level

​

I am on the latest version of 3dsMax 2025 if it help.s