CGTalk - Ambient Occlussion in MR

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anolanbfg

09-19-2005, 03:22 PM

OK

In using a Mental Ray Ambient occlussion shader to render out a lightmap I've notice that when I change the method to Occlussion it renders out good lighting but it seems to pick up what is almost a hard edge effect (even though they are not). It is very slight but enough to be a pain- so they'll appear as a slightly darker line tone. I've fiddled around with this and no luck.

Anybody come accross this problem before?

thanks

Sphere♥

09-20-2005, 04:26 PM

A picture is worth...

anolanbfg

09-21-2005, 09:55 AM

This should illustrate it better- You can see the edges are shaded dark.

http://tinypic.com/dwf134.jpg
(http://tinypic.com/dwf134.jpg)

akewt

09-21-2005, 10:18 AM

the top right hand torus shape looks like you have a hard edge on your model but the darkening around the edges of your model could be the ray spread setting. try setting it lower. looks like the rays are exceeding 90. other than that it look slike you coul dbe up the resolution of yuour model.

cheers
kev

joie

09-21-2005, 11:36 AM

What do you mean with "change the method of occlusion"?, may be that´s the problem...

mental

09-21-2005, 03:16 PM

just a thought... are you sure there is no other object(s), perhaps with primary visibility turned off, close by that could be generating a contact shadow?

anolanbfg

09-22-2005, 08:42 AM

thanks for the replies guys,

What do you mean by Ray spread settings? I haven't tried that and where can I find it?

All I mean is instead of say...Light and Color- I set the baking to Occlusion.

Yep, the scene is very simple and there are no other objects in there- it's clean.

thanks again

akewt

09-22-2005, 09:24 AM

well if your baking occlusion through the bake menu you wont get this option. you can only get it through the shader node.

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