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No motion blur with vertex groups?

Posted: Tue Jul 07, 2020 10:46 am
by cheeseburger
Trying to get motion blur on a character I imported as a .dae.
It seems that objects without vertex groups get blurred but the ones with multiple vertex groups don't get blurred. Is this a known situation? Is there a workaround?


Thanks

Re: No motion blur with vertex groups?

Posted: Tue Jul 07, 2020 4:18 pm
by linograndiotoy
Could you please better clarify the issue?

Re: No motion blur with vertex groups?

Posted: Tue Jul 07, 2020 5:22 pm
by cheeseburger
I have a character with various vertex groups imported as a .dae file. I've got motion blur working on parts of the character that don't have any vertex groups, but those bits that do i,e, face etc haven't got any blur happening. Hope that's a bit clearer ..

Re: No motion blur with vertex groups?

Posted: Tue Jul 07, 2020 9:50 pm
by linograndiotoy
cheeseburger wrote:I have a character with various vertex groups imported as a .dae file. I've got motion blur working on parts of the character that don't have any vertex groups, but those bits that do i,e, face etc haven't got any blur happening. Hope that's a bit clearer ..
Can you share the scene so we can take a look?
Vertex Groups have nothing to do with motion blur, so this sounds a little odd. Did you set Deformation on for the motion blur?

Re: No motion blur with vertex groups?

Posted: Wed Jul 08, 2020 11:42 am
by cheeseburger
Hi linograndiotoy, just PMed you with a file .. Thanks Very curious to hear what you think

Re: No motion blur with vertex groups?

Posted: Wed Jul 08, 2020 5:01 pm
by linograndiotoy
As I suspected, you just need to change the Object ype to Reshapable for all deforming meshes:
Cattura.PNG
Thanks!

Re: No motion blur with vertex groups?

Posted: Wed Jul 08, 2020 7:37 pm
by cheeseburger
I've tried giving all the geometry with vertex groups a deformation value of 8 as they don't seem to get blurred with lower numbers .. but I'm getting this weird artifacting (see pic).
Also, I've put all geometry to Reshapable Proxies.
Strange artifacts-Deformation8+ReshapbaleProxy.png

My big question is .. why does the hat and glasses etc (no vertex groups) come out ok and the other geo (with vertex groups) is different and difficult to manage? Can I set up an easy way of dealing with this? I have another 10-11 characters I'll need to fit into a scene.

(For some feedback to other folk ... I spent ages with a couple of animated files only to find that this [Reshapable Proxies] was the way to get Ocatne to refresh some animated geo and particles and spit out the correct rendered images - without that they'd all come out as a still image)

Re: No motion blur with vertex groups?

Posted: Wed Jul 08, 2020 7:52 pm
by cheeseburger
P.S. If I put a subdivion surface modifier on the face and body, the motion blur completely disappears ..

Re: No motion blur with vertex groups?

Posted: Fri Jul 10, 2020 9:23 am
by linograndiotoy
cheeseburger wrote:P.S. If I put a subdivion surface modifier on the face and body, the motion blur completely disappears ..
Yes, that's something I noticed.

I've found 2 possible workarounds for it.

First, try to select the meshes and make them "Smooth".
If this doesn't solve the issue select the mesh just add a Vertex Weight Edit Modifier just after the Subdivision Modifier.
You should see Motion Blur working fine now.

Re: No motion blur with vertex groups?

Posted: Fri Jul 10, 2020 10:43 am
by cheeseburger
Yey !! I tried Smoothing faces, edges, vertices and normal vectors and that combination worked ! Now I just gotta write me a script to do this automatically. A good excuse to buckle down with Python Fantastic .. Thanks :D