Maya for 3D Printing - Rapid Prototyping
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# 1 29-05-2017 , 10:21 AM
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Join Date: May 2017
Posts: 2

Render is wrong in Orthographic cam

Hi,

I have an issue when rendering xgen hair in Arnold. I'm using the same AlHair shader on all strands.

In perspective view, all strands correctly.

In any non perspective camera, the strands are rendered wrong. If I take a non perspective camera that renders wrong, and change its Camera Type to perspective in the Camera Attribute's Arnold tab, it renders correctly. If I switch it back to orthographic it renders wrong again.

Could you help me with this issue? I need to render those strands in an orthographic camera.

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# 2 30-05-2017 , 01:56 AM
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SM Tea Boy
Join Date: Apr 2002
Location: Prague
Posts: 3,227
It's a lighting issue i believe. See the shots below, as you can see it's the same thing you're getting. It's not an error adjust your lighting to get the look your going for in the orthographic view.

How much highlight you get on hair will depend on the light angle, this angle will change as you move the camera https://www.3drender.com/glossary/fresneleffect.htm

Adjust your light source/s see images below. First 2 are with the light in the same place as you can see i've replicated the issue your having. Last image is after i changed the direction of the light source

Hope it helps
David

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From a readers' Q and A column in TV GUIDE: "If we get involved in a nuclear war, would the electromagnetic pulses from exploding bombs damage my videotapes?"
# 3 30-05-2017 , 07:04 PM
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Join Date: May 2017
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Thanks for taking the time to do these tests David!

I've conducted the following test: creating a perspective cam that matches the orthographic cam almost 1:1 by playing with focal length etc. The result is: the perspective cam renders completely differently from the ortho cam even through they're framing exactly the same thing.

Therefore, I think it disproves this issue being created by the lights. What do you think ?

I guess I solved my problem by replicating the ortho cam's results with a perspective cam but I'm still curious why would the two cameras render completely different results...

# 4 30-05-2017 , 08:19 PM
David's Avatar
SM Tea Boy
Join Date: Apr 2002
Location: Prague
Posts: 3,227
Well that's weird to my knowledge that should not happen, i'm glad you got the result you where after in the end.

I'll have a play with xgen and see if i can get it to do the same thing i'd be interested to know why it's happening.


From a readers' Q and A column in TV GUIDE: "If we get involved in a nuclear war, would the electromagnetic pulses from exploding bombs damage my videotapes?"
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