Collada limitations and UnboundLocalError: local variable 's' referenced before assignment

[j.r.lewandowski@…]

The following bug report has been submitted:
Platform:        Darwin-18.2.0-x86_64-i386-64bit
ChimeraX Version: 0.9 (2019-02-14)
Description
I was trying to load a 3D objects in Collada format. I also tried gltf and obj - none of these loaded successfully. 
Is it a bug or is it that some of the features present in my models are not supported in ChimeraX and won't load? 

Log:
UCSF ChimeraX version: 0.9 (2019-02-14)  
© 2016-2019 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> open /Users/jozef/Desktop/DH/GB1-IgG-complex.cxs format session

opened ChimeraX session  

> view name test

> save session /Users/jozef/Desktop/GB1-IgG-complex-test.cxs

> open "/Users/jozef/Desktop/Rigged_Hand/Rigged_Hand_obj/Rigged Hand.obj"

OBJ reader only handles triangle faces, line 1775: "f 106/1/1 105/2/2 358/3/3
103/4/4 "  

OBJ reader only handles triangle faces, line 1775: "f 106/1/1 105/2/2 358/3/3
103/4/4  
"  

> open "/Users/jozef/Desktop/Rigged_Hand/Rigged Hand_dae.dae"

Traceback (most recent call last):  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/ui/gui.py", line 549, in _qt_safe  
run(session, "open " + quote_if_necessary(paths[0]))  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/core/commands/run.py", line 31, in run  
results = command.run(text, log=log)  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/core/commands/cli.py", line 2617, in run  
result = ci.function(session, **kw_args)  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/core/commands/open.py", line 41, in open  
from_database=from_database, ignore_cache=ignore_cache, **kw))  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/core/commands/open.py", line 117, in open  
models = handle_unknown_kw(session.models.open, paths, format=format,
name=name, **kw)  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/core/commands/open.py", line 62, in handle_unknown_kw  
return f(*args, **kw)  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/core/models.py", line 598, in open  
session, filenames, format=format, name=name, **kw)  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/core/io.py", line 467, in open_multiple_data  
models, status = open_data(session, fspec, format=format, name=name, **kw)  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/core/io.py", line 423, in open_data  
models, status = open_func(*args, **kw)  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/surface/__init__.py", line 60, in open_file  
return collada.read_collada_surfaces(session, stream, file_name)  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/surface/collada.py", line 29, in read_collada_surfaces  
set_instance_positions_and_colors(s.all_drawings())  
UnboundLocalError: local variable 's' referenced before assignment  
  
UnboundLocalError: local variable 's' referenced before assignment  
  
File
"/Applications/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-
packages/chimerax/surface/collada.py", line 29, in read_collada_surfaces  
set_instance_positions_and_colors(s.all_drawings())  
  
See log for complete Python traceback.  
  




OpenGL version: 4.1 NVIDIA-12.0.21 355.11.10.50.10.103
OpenGL renderer: NVIDIA GeForce GT 750M OpenGL Engine
OpenGL vendor: NVIDIA Corporation

[Eric Pettersen]

Reported by Jozef Lewandowski

[Tom Goddard]

Yes, your files are using features of OBJ and Collada that ChimeraX does not handle. Reading these files is a fringe capability of ChimeraX. It may be improved in the future if funding permits.

The OBJ file you are trying to read has quadrilaterals instead of triangles which are not handled by ChimeraX as indicated by the error message

OBJ reader only handles triangle faces, line 1775: "f 106/1/1 105/2/2 358/3/3 103/4/4"

The Collada reading problem is that no TriangleSets were found in the file. I've improved the code to issue a readable error message when that happens.

[Tom Goddard]

Elaine, might document if not already documented that OBJ reader only reads triangles (not quadrilaterals or larger polygonal faces) and the Collada reader only reads TriangleSets.

[Elaine Meng]

OK, for COLLADA I added “TriangleSets only” and for OBJ  changed to "triangles only: vertices, vertex normals, faces; no colors.”  If that still needs adjusting let me know - thanks!
Elaine