Revit LT 23 Repeatedly Crashing without Error Report (CER) when Panning / Zooming / Spinning in 3D

[a.henry.rose]

Hi Everyone,

Revit LT 23, ThinkStation p620, Windows 10, AMD Threadripper 3955WX 16 core, Nvidia Quadro RTX 4000 8gb, 32gb RAM

tldr; I think the culprit is a complex family I imported of a sofa that has subtle curves on the couch cushions. These only display in fine detail view. In medium, the family is built out of extrusions. I can't seem to reproduce the crash behavior in medium, for now. I'm hoping this is the solution. When opened in the family editor, the fully complex fine detail model has no issues. My theory is Revit is having trouble with the complex geometry when it is imported into the project. 

update: I confirmed this was correct after importing that sofa family from revit into rhino: the geometry was totally exploded and wierd. It was obvious Revit was not able to handle that level of complexity.

I thought I would share my experience with the last ~12 hours troubleshooting my model. It had been working fine, was mostly complete, and I was cleaning up the interior walls, stairs, etc. After a day I come back to it and it is crashing unexpectedly while zooming / panning in 3D. It does not generate an error report (CER). At first it may have given me the dialog "An error occured while drawing this view. Revit will now close this view..." I was able to save the model when it was stuck in this state, but I had to quit the program, it wouldn't open any after generating this error message.

That was so early in the saga I can't remember ... I didn't realize how protracted this would get. The standard behavior after that, reproduced probably 50 times, was a straight up crash, no warning, no CER, no freeze. Just about a 5 second stall with the model frozen on screen, and then the program quits. Always while panning / zooming in 3d, hidden line. I generated journal files from 117 to 173 below, all about 200kb, which shows how brief each session was. I have attached two of these below.

• I updated the graphics card driver, and some other BIOS / Lenovo stuff that I found could be updated. No effect.
• I brought up the Windows gamebar overlay (windows + G) to monitor the system usage before crashing. One thing that was pretty odd was I could get the GPU to spike over 90% while agressively panning / spinning / zooming the model. In an older (non-crashing) version of the model, this same behavior could only get the GPU to about 25%. 
• Even though Revit says my graphics card is compatible, I toggled off hardware acceleration and draw while navigating. No effect.
• The next approach was to read a ton on forums about proper file hygeine. My file had a couple of things that concerned me. One was mirrored and nested groups -- I read something about how this can cause erratic behavior. I've had them in the model for a long time, so I doubted this was the issue, but I ungrouped all of them. No effect. Maybe that warning is for an early build.
• I tried purging unused things to lighten up the model, but it was only 300mb, and purging these things barely changed the size. Then I started systematically deleting model elements I remembered doing most recently. 
• Finally, I got to the **** couch, discussed at the beginning, which was a relatively late addition to the model. Oddly, it did not start causing the program to crash immediately after importing it, so I'm not sure why it took a while to cause the issue. So far though, the solution noted above, to only view the model in medium detail in 3d views, has worked. I will update if this changes. I have included a link to the couch family below. 
• In the model's current state, with the modified couch (I created another family that only displays the simplified geometry at all detail levels) I can only get the GPU to spike to 38% with aggressive navigation. My theory is that Revit was somehow overtaxing the GPU before ... the odd thing was that before some of my crashes I barely touched the model. Just a simple rotation after opening it, one single move, could cause it to crash. More often than not, it was during a more complicated procedure.

I am scheduling a call with Autodesk tomorrow to go over this. I'm hoping they can help me understand the journal files. I'll update if I learn more. This was the biggest issue I've ever had with the software, and a serious waste of time. I hope this might help someone else, and I'd love the insight if someone can shed light on the behavior I am describing. 

Cheers.

Hank