Issue with geometry randomly disappearing from the arnold render view

[Anonymous]

So I'm currently working with Maya 2019 but I've had this same issue in the past while working on other versions of Maya. It doesn't seem to happen too often but its very frustrating when it does. 

I was using isolate selected while running the IPR and messing with sliders on a ramp node when suddenly my entire mesh dissapears from the render view.

I'm working on a skin shader for a human bust and the bust will dissapear but eyes remain visible in the render view. I try everything to get it back into view and sometimes I'm unsuccessful and sometimes it will seem to reappear for no reason. I've tried assigning a new arnold material, deleting the mesh and re-importing it, I deleted my preferences, I updated arnold, I made sure it was on the correct render layer, I made sure camera visibility was checked, I've tried restarting maya and my PC numerous times.

Doing random things like like turning autobump off on the mesh shape will get it to come back, or changing the catclark subdivs to a different amount. But doing random things like changing a slider on a node will cause it to vanish again.

The strange thing is the mesh is always visible in the regular render view but not the arnold render view, which sucks because the arnold render view seems much faster and has the isolate selected mode. 

If anyone has any clues as to what causes this I'd be very grateful to know. 

[cheynecg]

I've had this happen to me as well. If you click on your mesh in the viewport while it's rendering you should see the wireframe appears in the Render viewport to show that your model is still there. I'm assuming you're rendering using Arnold. If you're changing any Render Settings or plugging in new shaders, make sure to update your scene through the render window or Ctrl+U. Also make sure your lights are active and not hidden. If you're isolating your object to render it, you probably don't have lights in the scene.

[Anonymous]

I am using arnold and no, I click on my mesh in the viewport there is no wireframe in the render view. Even when I click in the renderview where  my mesh would be, nothing highlights, as if its not even there. I do have lights and they are active in my scene, since I can still see the eyeball geometry in my render view. I'm using isolate selected on nodes in the hypershade to view my different maps, not the meshes themselves.

But regardless when I have isolate selected turned off my mesh still isn't visible. I literally just changed the render cam and it came back again, I saved and closed it out. Went out to see a movie, I just came back home and now its gone again, and now it makes no difference which render camera I use. I'm really at a loss here. 

[cheynecg]

Would it take too long to rebuild the asset in a new scene? I would go through the scene and start turning things off/removing to narrow down the issue and identify the problem. Hope you get it working.

[Anonymous]

No it wouldn't, and I was considering just rebuilding everything in a new scene, I suppose that's all there's left to try. Just not sure how to export my Arnold shaders out but I guess I'll look it up later. Thanks for the suggestions though, I appreciate it. 

[damaggio]

There’s no need to rebuild anything, this can be easily fixed.

[Anonymous]

I'm not talking about actually remodeling anything, just moving my assets and shaders to a fresh scene. But if you have any other solutions I'd be interested in hearing it. 

[Anonymous]

So I re-exported everything out of zbrush again. My mesh, my displacement maps, and everything else. I exported my shaders out of my old Maya scene and set everything up in a fresh scene. New Lights, new camera, new render settings. Worked for about 5 minutes and it disappeared from the arnold render view yet again. Just spent 5-10 minutes rebuilding a whole new skin shader from the ground up to see if the shader was the issue, it worked for a second and while I was adjusting my displacement settings it disappeared again. This is increasingly becoming more and more frustrating and I'm not sure how to continue from here.  

[sean.heasley]

Hi @Anonymous 

What GPU are you using and is the driver version the same as our certified hardware list?

You can find our certified hardware list here!

Also, if you create a basic scene set up with some cubes and render does any of the disappearing happen?

Finally, while it may look fine in the viewport, can you check to see if the normals are flipped? That could lead to not seeing it in the render.

[Anonymous]

I'm using a gtx 1050ti, I remember you telling me before that my GPU isn't officially supported and I don't see it on the list. I did update to the recommended drivers a week ago because I figured it might fix the issue but it didn't affect anything. 

I have no issue rendering basic shapes in a fresh scene, nor do I have an issue rendering other assets in my main scene, it just seems to be my human mesh that disappears from the IPR. I had this same issue with a project last year I was working on, everything would seemingly render fine but one specific mesh would always vanish from the IPR. 

I also checked the normals on my mesh and they're fine. 

[mspeer]

Hi!

I don't think the problem is related to the GPU, but instead of guessing and testing for several days, i recommend to upload a scene-file + the exact steps how to reproduce this.

[sean.heasley]

Hi @Anonymous 

Thanks for the update!

I believe @mspeer  has the right idea and at this point we need the file.

When you get a chance, can you please zip and attach the scene file here or via dropbox/google drive or another file sharing program so I can take a look at it? If the file is confidential or under NDA please send it to me in a private message instead of posting it here.

[mspeer]

Hi!

@Anonymous 

Please also make sure to use the latest Arnold version (MtoA 3.2.1.1).

[Anonymous]

So I opened my scene, had one window with the arnold renderview with IPR active on rendercam_001, and another window with the hypershade open. I was checking out my micro displacement in the render, unplugged it from the displacement shader, plugged in the base displacement, then unplugged it again and connected my micro disp back up and the mesh was gone again. If I disconnect and reconnect the other displacement it makes no difference. 

The folder on my dropbox has the scene file and both sets of displacement UDIMs, please let me know if you need anything else. 

Also, @mspeer my version of arnold is up to date. 

https://www.dropbox.com/sh/d6ckqgul12l6cby/AADQs_CxBQL2JvrVetsJ3a0Ba?dl=0

[mspeer]

Hi!

I will check this, but changing scene setup like breaking and creating new connections may require "Update Full Scene", this is normal.

[Anonymous]

Believe me I've tried updating the full scene haha 

[mspeer]

Hi!

I was not able to reproduce this here, however i used Maya 2019.1, which may be the reason why it works here.

I also recommend to disable subdivisions for your character to check for memory issues.

As said before, some drastically changes to scene setup may require a "Full Update".

[mspeer]

Hi!

Also care when mixing Auto create TX textures and then using some TX textures directly (duplicates).

Creating an Arnold log with Debug mode may show the problem.

[Anonymous]

I don't understand much of what the log says but once my geo disappears it's saying all of my UDIM files are broken. I couldn't find where my log file was saving to so I just copy and pasted a chunk of the log into a txt file, from the point where the geo was visible and when it disappeared. 

https://www.dropbox.com/s/gutt3y4m29wlfy9/arnoldlog.txt?dl=0

[jewboy0117]

I have the same issue. I noticed that this mesh disappear issue reverts once you turn off the displacement on the model itself. I still am not sure why this occurs.