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Doum

Rop alembic and "Use Motion Blur"

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Hey all,

I hope someone can shed some light on this. I'm trying to understand the motion blur in the rop alembic OUT node.

I need to make them match with XSI, that why I need to understand them better.

Here what I think, correct me if I'm wrong...

- If I check the "use motion blur" box :

Samples : 0

Linear interpolation with no motion blur sub-frames. (ie frame: 5 / 6 )

Samples : 2

2 sub-frames (ie frame: 5 / 5.33 / 5.66 / 6 )

The Shutter also give me interrogation:

The XSI default is set to 0.25 - 0.75. Do I need to make my ROP alembic Shutter match with the one from XSI ?

thanks

Doum

After some test, I've clarified the meaning of these setting and make them match in XSI(arnold).

- If I check the "use motion blur" box :

Samples : 2

mean 1 sub-frames and the next frame. (ie frame: 5 / 5.5 / 6 )

Samples : 4

mean 3 sub-frames and the next frame. (ie frame: 5 / 5.25 / 5.5 / 5.75 / 6 )

For the shutter part, it's seam to clip between the values you give. Sorry, I'm not able to explain in number what it would gives, but I let it to the default values 0-1.

I hope it could help someone

Edited by Doum
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I tried to export fluid simulation from houdini in alembic format with motion blur activated, But in Maya no motion blur appear with vray or Arnold ...

Anyone achieve to get a nice motion blur with Alembic export from houdini ?

Any Idea ?

Edited by Tylius

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It gives me an error when I try to render an alembic fluid from houdini with arnold in xsi. It give me "wrong number of normal indices" error...

did you tried the .bin format?

Doum

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I'm currently testing to export particles with copied spheres on to render in maya and vray. I got it to work when I set motion samples 2 (as mentioned above 1 sub frame and the next frame) in houdini and set shutter angle to 180. when rendering with vray, maya jumps to a subframe (shutter angle == 0.5 frames) so maybe maya needs to be on that exact subframe when rendering, though I don't know how to calculate the different subframes for different shutter angles.

we also tried to write out .bin with realflows plugin to houdini, then from realflow to maya. It workt great, but in my mind that makes a unnecessary step...

Mike

Edited by Mikael

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Hey Mike,

Did you try to offset the shutter, in XSI you can set the shutter on 3 "position". start on frame, center on frame, end on frame. Look like only end on frame give a correct result.

Shutter position:

start on frame : current frame --> next frame

center on frame: between previous frame and current frame --> between current frame and next frame

end on frame: previous frame --> current frame

I hope it help you

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