This is what Blender is rendering I found even more bugs. https://www.youtube.com/watch?v=e1ScHjBANLk

The scene is 12 GB in size with maps and all, will need to work out a delivery method.

One should reduce the scene objects just above till it doesn't happen anymore.

In T76268#921032, @Ankit Meel (ankitm) wrote:

The scene is 12 GB in size with maps and all, will need to work out a delivery method.

One should reduce the scene objects just above till it doesn't happen anymore.

I deleted objects and scaled all the maps down till the scene was only consuming 4GB of memory same result shadow just disappears randomly.

Figured it out, It has nothing to do with file size or object complexity. I deleted the volume light box with just a 1000 floating sprite boxes for the dust inside the garage. After that, the issue went away all together. I then added the volume box back and the problem happened again. It must have something to do with volume lighting. The grass outside is over 12k clones using a particle hair so it has something to do with volume lighting and particles inside a object. If Blender is really serious about winning over Max and Maya users, then get back to me I can send the scene via a zip file. I tested the same scene out on my other box and the problem happened. Both machines are running RTX 2060s. One is a Intel box and the other AMD.

In T76268#921372, @Ankit Meel (ankitm) wrote:

then get back to me I can send the scene via a zip file.

It was asked in the form itself. Please remove extraneous elements which totally do not contribute to the bug. A better approach would be to bring problematic objects only to a new blend file and upload the zip.

What's the deal with no pause or stop rendering on an animation?

I think esc should work ? If not, I just close the render window and I'm back to the main.

Roger that will do

Around frame 60 if you render the animation 1-300 the shadow will disappear. Escape the render… The viewport will continue to display the shadow. But after the shadow disappears during the render and without closing and reopening Blender whenever you render a frame the shadow “sun light” is absent.

It’s not every 50 frames sometimes its 3 when you are closer to the volume lighting if you close blender and start it up again from the frame the shadow disappeared from it will maybe render 2 or 5 frames before losing the shadow. Its random but a bug never the less.

The issue happens because the instanced object (OBSphere.001) is wrongly evaluated and has NaNs in place of its obmat. Leading to an infinitly large cascade.

So this is a particle system issue.

The bug disapear if the number of particle changes (I guess the cache is cleared) so I don't know if that's because of the cached data or if the simulation of this particular setup is causing the NaNs.

Here is a much simpler file to test with.