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-   -   Bump, Normal or displacement? (https://simplymaya.com/forum/showthread.php?t=35030)

Rhetoric Camel 29-01-2011 10:19 PM

Bump, Normal or displacement?
 
How do you know where and when to use each one of these?

honestdom 30-01-2011 12:29 AM

hasn't this been covered many times on these forums?

Rhetoric Camel 30-01-2011 12:40 AM

yeah, sorry. Search function wasn't working when I made the post for some reason but it is now. *deletes post*

Jay 30-01-2011 11:46 AM

Well however many times its been posted, a refresh is always good.

Well bump maps and normal maps are almost the same thing really as neither of them distort the geometry in a physical way like a Displacement map does. Normal maps are regarded as a super bump map as it uses the direction of surface normals of a model to give the impression of it being bumped, they do look better than your standard issue bump though for sure.

Bump maps and Displacement maps are only similar in the fact that they are coloured black thru to white ( values 0-255, black being 0 and white being the uppermost threshold of 255 )

Bump maps work pretty much for anything, and can be used to a good effect on long to medium work but can the closer you go the more they will finally give way. But that is where you decide whether or not you are gonna need a dis map to show of the surface of the model is actually physically bumpy. Bump maps are reliant on light angles to show them off well and from a certain distance as Ive already said.

However displacements also can be disadvantageous, as UVs need to be good -seriously good if using them on hardsurfaced models. I have had many discussions with CG supervisors on them as some prefer them some dont. My Supervisor right now would prefer not to use them on hardsurfaced models and stick with bump maps or have the models with the detail there. At the end of the day you cant beat the geometry - Avatar used geometry for all the facial expressions of the characters, as dis maps caused problems when animating (swimming and blurred textures) .

hope that helps for now - gotta go out !!

Jay

Rhetoric Camel 30-01-2011 05:14 PM

@Jay - Although I found my answer and went with the bump map for my hard surface model. I really appreciate you taking the time to answer.

Jay 30-01-2011 06:17 PM

Excellent - :)

Ahh no worries. These things do cause dilemmas. Just to clarify, any of these types of maps do have their own problems and one is not necessarily better than the next - it just has to do a job and look convincing depending on how it will be viewed.

Ive helped create some 8k bump maps over the last year and when you see the final animation they look fine and nobody would even know.....so its horse for course as they say.

cheers
Jay

ctbram 03-02-2011 11:57 PM

1 Attachment(s)
On the subject of displacement, I have been experimenting a lot with them and they are really finicky in maya. Mental ray and maya materials seem to have significantly different behavior.

Here was the test I did on my lego model. The "lego" text is a displacement map on a mental ray mia_x material.


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