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royter
11-02-2009, 04:28 PM
here's a simple sphere moving from one side to another.
i am getting some strange squares on it, any ideas what's that? i tied crancking up my samples with no success (FG,mia sky/sun,mia exposure simple).

scene (http://sor.typepad.com/files/3d-blur-issue.ma) (right click save as)


http://sor.typepad.com/.a/6a00d8350600cb53ef0120a64adfb2970b-800wi

glxtrix
11-02-2009, 07:12 PM
turn your MB settings back to normal...

Motion blur by = 1
Shutter open = 0
Shutter close - 1

Displace Motion Factor = 1
Motion steps = 1
Time samples = 8

Then select your ball and press the number 3 to smooth your object....or do a mesh smooth. That should work. Under the mia_physicalsun1 you can also turn up the samples...however you will increase render time, and I didn't do that to fix your issue.


To further optimize your scene (based on what you have now) you can also turn your raytrace down:

Refl = 2
refr = 2
Max trace = 4

Shadows = 2
Refl blur = 1
refr blur = 1

royter
11-02-2009, 08:06 PM
turn your MB settings back to normal...

Motion blur by = 1
Shutter open = 0
Shutter close - 1

Displace Motion Factor = 1
Motion steps = 1
Time samples = 8



these values didn't change a thing, only the "Motion blur by"=1 attenuated the artifact a bit , But this is not an option since i need to motion blur some moving particles in my scene and some other objects.


Under the mia_physicalsun1 you can also turn up the samples

it didnt fixed the artifacts.


Then select your ball and press the number 3 to smooth your object
this worked by oversmoothing my sphere 2 times, but this is not a clean solution since i will have to oversmooth every single moving object in my scene.

glxtrix
11-02-2009, 08:42 PM
Well, from what I see, it seems to be a geometry issue...it's faceted and the shadows are saying so, hence why I smoothed it. Hopefully someone else will chime in. Cheers.

royter
11-02-2009, 09:01 PM
Well, from what I see, it seems to be a geometry issue...it's faceted and the shadows are saying so, hence why I smoothed it. Hopefully someone else will chime in. Cheers.

my normals are soft, and when i render without motionblur it looks correct.
i applied a MR approximation editor and it fixed that problem but thats memory consuming and its not the ideal fix. i dont understand between geometry tesselation and motion blur.

Eshta
11-02-2009, 09:45 PM
Are you sure this is from motion blur ?
it looks like "terminator" effect ...shadow on object not smooth
try subdividing your object

Eshta
11-03-2009, 02:16 PM
I smothed your mesh and now it works fine

royter
11-03-2009, 04:09 PM
I smothed your mesh and now it works fine

i know, it works but smoothing every mooving objext in my scene is not an option.

Eshta
11-03-2009, 04:32 PM
if you use Maya 2009. just press 3 on the keyboard > that smooth preview (fix as well)
Or
Move the light slightly
Or
override the shadow

The terminator effect was described in the docs...cant find it now..its a shadow problem with direction light and raytrace

Ash-Man
11-03-2009, 09:48 PM
Eshta is right
you might want to look in this as well
http://www.lamrug.org/presentations/oct2004/mental_ray_for_maya_dynamic_attributes.htm

phix314
11-03-2009, 10:51 PM
I've had similar issues with the rasterizer. I have yet to find a solution. I heard something a while back about tile sizes or somesuch thing.

royter
11-04-2009, 04:21 AM
Eshta is right
you might want to look in this as well
http://www.lamrug.org/presentations/oct2004/mental_ray_for_maya_dynamic_attributes.htm

man.....this is so unacceptable, i understand that artifacts can show in a a complex scene but a simple sphere with 1 directional light and motion blur comes out with artifacts. I dont know what to say i just hope that Vray4Maya pushes mentalimages to do better.

Cheesestraws
11-04-2009, 09:37 AM
But this problem is exasperated by it being such a simple scene with a low resolution sphere. It is a general problem with raytracing and normal interpolation.

glxtrix
11-04-2009, 02:36 PM
Seeing that the blur on the sphere is soooo minimal, why not just render with no blur out of maya (because we know it renders fine w/o mb) and then just add a blur in post....or use RSMB.

royter
11-04-2009, 04:27 PM
Seeing that the blur on the sphere is soooo minimal, why not just render with no blur out of maya (because we know it renders fine w/o mb) and then just add a blur in post....or use RSMB.

i am rendering a scene with some blured falling snow so this is why i need motion blur.
Besides rendering animations with no motion blur is never an option for me.

Cheesestraws
11-04-2009, 04:49 PM
why are you using large opaque spheres for snow?

royter
11-04-2009, 07:29 PM
why are you using large opaque spheres for snow?

just to check how MB is affecting other objects
movie (http://sor.typepad.com/files/comp-1.mov)

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