Re: motionblur...AGAIN

["Andy Jones" <andy(at)thefront.com>]

I haven't spent much time dealing with the motion vector framebuffer, but on the topic of unpremultiplied vector data, isn't that what you'd want?  The edges of the object don' t move any less than the object itself, right?  Even if there is partial coverage?  Is it possible that AE is "expecting" a premultiplied image, and that's why you're having to multiply the alpha?

I'm not sure about the other problems.  We're still doing our rendering on 5.11 as well (and getting pretty darn sick of it).  C'mon, lucky number 7...

- Andy

On 11/6/07, Jeff <jeff(at)magneticdreams.com> wrote:

Here is the image I sent to SI. I'm not sure what you mean by lens shaders but I want to know.

http://www.magneticdreams.com/Motion_Buffer_Issue.jpg

You can see the feet eroding to gray. I would love to get this working.

-Jeff

m i c r o x x wrote:

Hi Jeff,
             I dont completly understand what you mean with "chunks of
the object flash from
grey to the vector color. I think it depends on if it's moving or
not." but i found that mv framebuffer are kind of a lens shader. I had

problems with a scene where only the moving objects were rendered in
the mv framebuffer but then i turned on lens shaders and everything
rendered correctly: the moving objects with the motion info and the
static with the purple color.


The unpremultiplied output is really simple to correct, but i think it
would be nice if we could skip that step: i don't know if somebody
needs a motion pass without the alpha premultiplied for something, but

i think most of the people dont.

And the offset thing is really weird, i use the motion framebuffer all
the time and never had and offset, even with deforming objects.  In
that particular case i think you need to contact Softimage directly.


Orlando.


On Nov 6, 2007 9:38 AM, Jeff <jeff(at)magneticdreams.com> wrote:
  

 You are supposed to be able to use the motion framebuffer instead of
rendering another pass with a MV shader. However we are in the same
situation as you. We moved to XSI 6.5 from 5.11 because we were tired of

paying for the maintenance and not using the latest software. So in the last
project I used the framebuffers for motion. They work somewhat, but it does
not kick out an alpha (the bg is grey) and chunks of the object flash from

grey to the vector color. I think it depends on if it's moving or not. I'm
about to send Softimage an email about this, but I did find a few
workarounds.

 Kick out the motion buffer as 16bit SGI.

 I had to use After effects for comping, and the realsmart motion blur
plugin works with the motion framebuffer. But you have to precomp it and
apply the color channels alpha to the vectors. Also to fix the grey blocks

appearing, I used primatte to mask out the grey color, and put a purple
solid that matches the motion vector color when it's not moving. This is a
ridiculous workaround to something that should be working!


 In the end it worked but it was so much work, we are thinking about moving
back to 5.11.


 -Jeff




 Daniel Jahnel wrote:
hi everyone...

 [Rant_start]
 so we're giving 6.5
 a chance here now...first thing i try is motionblur.
motionvectors dont seem to work properly, i always get some offset in my
motionvector pass in comparison to the beauty pass, even if i set shutter to
"end on frame". if i set speed to 0 it works but i dont get any

vectors...great. how am i supposed to use these settings?? its completely
confusing that you have a shutter speed in the renderer and some dubios
shutter-open-close parameters in the scene...why is motionblur always a pain

in xsi?? for many versions its just constantly broken and unusable at times
and one always has to fight it....dont people use motionblur?? back to
reprojecting then...
 [Rant_end]

 Daniel

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Jeff Greulich
 Senior 3D Modeler/Texturer



Magnetic Dreams Animation Studio, Inc.
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 Ph  615.885.6801 | Fx  615.889.4768
 | www.magneticdreams.com
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Jeff Greulich Senior 3D Modeler/Texturer

Magnetic Dreams Animation Studio, Inc.
2525 Lebanon Pike, Building C. Nashville, TN 37214
Ph  615.885.6801 | Fx  615.889.4768 | www.magneticdreams.com
jeff(at)magneticdreams.com

Confidentiality Notice: This email, including attachments, is confidential and should not be used by anyone who is not the original intended recipient(s). If you have received this e-mail in error please inform the sender and delete it from your mailbox or any other storage mechanism. Magnetic Dreams, Inc cannot accept liability for any statements made which are clearly the sender's own and not expressly made on behalf of Magnetic Dreams, Inc or one of its agents.