I had a head-scratching moment earlier today with what appears to be a bug in DipTrace's handling of 3D models in STEP format. Thought I would give others a heads-up about it to save anyone from suffering from the same problem.
I had downloaded a 3D model of a part from the
JST website, and went to load it up as the 3D model for a component on my PCB layout. Except, when I opened the file, nothing would happen. The 3D model preview would continue to be empty, as if I'd never asked DipTrace to load a file in the first place.
![Huh? ???](https://www.eevblog.com/forum/Smileys/default/huh.gif)
What was puzzling was that a second STEP model I'd downloaded beforehand worked just fine, so it must have been something to do with the file. Comparing the two in a text editor (STEP is a text-based format), I noticed the first non-working file contained some 'garbage' characters in the header section. I figured they may be Japanese characters, so I changed my editor's encoding setting to Shift-JIS. Ta-da, some intelligible text appears! On a hunch I deleted the text (everything between the single quote marks) and tried loading the file in DipTrace again. It worked!
![](https://www.eevblog.com/forum/diptrace/possible-bug-with-step-3d-models-containing-non-ascii-text/?action=dlattach;attach=426007;image)
So, if the same problem happens to you with any STEP file, I encourage you to load it up in a text editor and check for non-ASCII text in the header. If so, try deleting it and re-loading the file.
I have reported this bug to DipTrace support, so we'll see what they make of it. Hopefully they will at least change the code to make DipTrace show an error message when it fails to parse a file, rather than silently abort.