Strange artifacts when rendering with bump map

# 1 06-12-2009 , 12:13 AM

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Strange artifacts when rendering with bump map

Im working on my elephant's bump map but when every I try to start on a new area I get strange artifacts appearing (see image) (they don't appear on parts I have already done). I've checked the image file (.png) and there not on that. Any ideas what's causing them?
Thanks
Elephantinc

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# 2 06-12-2009 , 01:08 AM

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Re: Strange artifacts when rendering with bump map

Originally posted by elephantinc
Im working on my elephant's bump map but when every I try to start on a new area I get strange artifacts appearing (see image) (they don't appear on parts I have already done). I've checked the image file (.png) and there not on that. Any ideas what's causing them?
Thanks
Elephantinc

Originally Posted by

Did they appear on parts you have done and then disappear?

How are you making your bump map?

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# 3 06-12-2009 , 01:21 AM

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Check to see if the uvs are ok.

Imagination is more important than knowledge.

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# 4 06-12-2009 , 06:33 PM

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The UV's look fine. I've noticed them on bits I did at the start now as well (they were a lot smaller so I didn't see them earlier)
I'm making the bump map in photoshop, drawing all the lines by hand with the brush tool.
It definitely seems to be a problem in maya as they don't appear on the image file itself.
I'm rendering with mental ray
I'll try a different file format and see if that helps

edit: come to think of it, I did have to change the UV's slightly (although not on any part that I had already bump mapped) so I'll try reassigning the shader as well.

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# 5 06-12-2009 , 10:11 PM

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None of those worked, any other suggestions?

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# 6 06-12-2009 , 10:49 PM

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Why are you rendering with Mental ray? It seems silly at this moment, as you're working on textures; not shaders.

Try switching it over to software and see if it's better.

Imagination is more important than knowledge.

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# 7 07-12-2009 , 02:07 PM

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wow! I must be color blind. All I see is a black screen with a red square?

I thought it was my screens gamma but I recalibrated the monitor and it's fine.

I had to save the image bring it into photoshop in order to see anything. lol. It sure looks like it's picking up bump information. Maybe post the texture file so we can take a look at it?

"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675

Last edited by ctbram; 07-12-2009 at 02:10 PM.

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# 8 07-12-2009 , 05:19 PM

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I tried software as well and I had the same problem, I was only rendering with mental ray because I forgot to change it

@ctbram it sounds like a gamma thing. A few months ago I changed my gamma to 2.2 (it was 1.8) to make it the same as the rest of the world, do you know what setting yours is on?

Heres my file:

edit: oops, sorry about that, I forgot it embedded the images automatically

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# 9 07-12-2009 , 10:32 PM

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Are you planning on using MR for your final render? If so, then why wouldn't you use it to conduct the test renders? Iits not like MR shaders, FG and caustics are mandatory when using it.

It seems to be a problem with the file format, don't know whats up with png I rarely use it so I'm stumped. I tried .jpeg and I still got artifacts even when it was saved at max quality. Saving it as a .bmp solved the issue.

user added image