Problem changing materials inside frame_change_observer

[DanRathbun]

@dan20047

New to ruby scripting and posting here. … I’m having some success but still befuddled with modules, classes, etc.

Do not skip the step of leaning to understand modules and classes. They are required for Ruby, and for deploying code in a shared environment such as SketchUp’s Ruby ObjectSpace.

Without modules, you code can clash with the code of other author’s. So ALL of your code must evaluate within YOUR unique module namespace. It is also suggested that within that module namespace, that you separate each of your plugins / extensions within a uniquely named submodule.

@dan20047

I have many years of amateur experience programming autolisp for CAD.

This will not help much as Lisp is a 100% functional language. Ruby is a dynamic, multi-paradigm, procedural, 100% object oriented language. And in addition, within SketchUp it becomes event-driven by the user. (Even a sequential block of code must be fired by the user in some way such as chosing a menu item or clicking a toolbar button.)

In order to really code well, you must first learn basic Ruby constructs.

Ruby Learning Resources [WikiLists]

All seven of the lists below are set as wikis. INDEX PRIMERS & GUIDES BOOKS TUTORIALS REFERENCE TEMPLATES NEWS IDEAS

SketchUp’s API adds extensions to the Ruby core modules and classes.

@dan20047

However when I insert into the frameChange callback in scenes_v2.rb (ref below), the materials are removed instead of being replaced, and the undo breaks.

First off, that code example is written to ONLY work upon Dynamic Components. Not upon normal components, not upon normal groups, not upon primitive geometry.

The example model you have posted does not use any Dynamic Components, so the code example you used would not apply anyway.

@dan20047

I would like to automatically change all materials in the model when the scene changes.

Please be specific about what kind of objects you want this to work upon. IF it is ALL objects and ALL materials, then perhaps you need a different approach. It may be better to manipulate the materials collection rather than all the object’s material assignments.

@dan20047

… or are you not allowed to make changes to the model during an observer call-back?

In some observer callbacks the answer is NO (and the docs mention this.) Basically any “onChange” type of callback could go into a vicious endless loop if your code makes changes within it (resulting usually in a memory stack overflow.)

@dan20047

Am I dealing with modules/classes incorrectly …

Attached is a sketchup model and my modified scenes_v2.rb code → _draftMatChanger.rb

Yes your code is incorrect:

• You have not changed the toplevel Author module namespace to your OWN uniquely named module.
• You have not indicated in the file preamble what you changed.

Can you confirm that you are still working within SketchUp 2014 and what edition (Make or Pro) ?
(Looking at the file, it is saved as a version 14 model. The oldest version I have installed is 2016 so I could not exactly test in your situation.)

Also, you appear to have not yet installed the 14.1 maintenance update. Why?

See:

• https://help.sketchup.com/en/sketchup/older-release-notes