RhinoCommon: unable to get RenderMaterial of object

Scripting
, ,
1

Hi all,

In a python script I’m trying to retrieve the renderMaterial of an object, but it seems I’m not doing it right. This returns an error:

import Rhino

objTypesFilter = Rhino.DocObjects.ObjectType.Brep & Rhino.DocObjects.ObjectType.Mesh
rc, objRef = Rhino.Input.RhinoGet.GetOneObject( "Select object", False, objTypesFilter )

obj = objRef.Object()

renderMaterial = obj.Attributes.RenderMaterial

In my defense the error is not super helpful:

image
image769×156 3.5 KB

I’m testing this script on the most simple object possible:
sample.3dm (65.6 KB)

My Rhino version:
Rhino 8 SR8 2024-6-11 (Rhino 8, 8.8.24163.12481, Git hash:master @ ded4d86ca901dbeaf13ee84f79b3e91b22da4880)

What is the right way to get the renderMaterial of a RhinoObject in RhinoCommon ?

2

Hello- something like this perhaps

import Rhino
import scriptcontext as sc

objTypesFilter = Rhino.DocObjects.ObjectType.Brep & Rhino.DocObjects.ObjectType.Mesh
rc, objRef = Rhino.Input.RhinoGet.GetOneObject( "Select object", False, objTypesFilter )
mats = sc.doc.Materials

obj = objRef.Object()
attrs = obj.Attributes
idx = attrs.MaterialIndex

if idx != -1:
    renderMaterial = mats[idx]
    print renderMaterial.Name

-Pascal

3

Thank you @pascal

Your script above works nicely to get the material from the object in the 3dm file I sent in my first message.

If I try again on the same object in a scene where there are other objects, I get a new error:

image
image802×170 3.66 KB

Here is the scene: bla.3dm (415.7 KB)

The object that worked-but-now-doesn’t is this one in red:

image
image954×856 79.1 KB

doesn’t RhinoObject.Attributes.MaterialIndex return the index of the Material in sc.doc.Materials rather than the RenderMaterial in sc.doc.RenderMaterials ?

4

Hi Felix - sorry - use

sc.doc.Materials

-Pascal

7

@felix.mariotto RenderMaterial is directly on the RhinoObject ( https://developer.rhino3d.com/api/rhinocommon/rhino.docobjects.rhinoobject/rendermaterial?version=8.x# )

import Rhino

objTypesFilter = Rhino.DocObjects.ObjectType.Brep & Rhino.DocObjects.ObjectType.Mesh
rc, objRef = Rhino.Input.RhinoGet.GetOneObject( "Select object", False, objTypesFilter )

obj = objRef.Object()

renderMaterial = obj.RenderMaterial
print(renderMaterial)
2 Likes
8

thanks

-Pascal

9

Ah great, thank you both a lot !

10

By the way, when obj.RenderMaterial gives you None then no material has been assigned, and you should use the default material. This is just an instance of the default plaster material. Here a small update with default material usage:

#! python3

import Rhino
import Rhino.Render

defaultRenderMaterial = Rhino.Render.RenderContentType.NewContentFromTypeId(Rhino.Render.ContentUuids.PlasterMaterialType)

objTypesFilter = Rhino.DocObjects.ObjectType.Brep & Rhino.DocObjects.ObjectType.Mesh
rc, objRef = Rhino.Input.RhinoGet.GetOneObject( "Select object", False, objTypesFilter )

obj = objRef.Object()

renderMaterial = obj.RenderMaterial

if not renderMaterial:
    renderMaterial = defaultRenderMaterial

print(renderMaterial)
1 Like
11

@nathanletwory thank you for the precision !