transfer maps - bump map
 

hi Im doing a tutorial which uses a bump map from a high polygon mesh (thread for a tyre)

he uses a program Xnormal which is pc only I believe to bake a bump map from the mesh.

Is there a way to do this in maya?


Thanks
Graham

yes you want to create a normal map. There is a free tutorial on site that covers this. You can also google normal mapping and transfer mapping in maya.

http://simplymaya.com/autodesk-maya-...=156&sub_cat=0

but id like to make a bump map rather than a normal map, or is there a difference?

Have a look in the maya help files mate...it explains it a little in there.

Cheers bullet

Yes there is a difference. The bump map simply requires a greyscale image and a low poly mesh. The normal map generally starts with a high poly and low poly mesh and the high poly meshes detail is baked onto the low poly mesh. Both are just a lighting trick there is no actual geometry. From your description it sounded like you had a hi-poly mesh and wanted to create a normal map.

You should be aware that a bump map will only create the illusion of treads it will not actually displace the geometry so if you get to close or you view the treads edge on you will see that there is no actual tread geometry.

Here is an example for you...

1. make a simple tire and uv map it...This is just a simple cylindrical map with the seam at the bottom of the tire.
http://i181.photobucket.com/albums/x..._uvMapTire.jpg

2. paint a bump texture in ps...50% grey == no offset, pushed in < 50% < push out.
http://i181.photobucket.com/albums/x...p/th_outUV.jpg

3. here is a render without bump...
http://i181.photobucket.com/albums/x...eadBump_02.jpg

4. here is a render with bump applied...
http://i181.photobucket.com/albums/x...eadBump_01.jpg

not sure, but i think he was asking if you can bake normal maps in maya, not asking how to make a bump map.

you can bake a normal map in maya by going to the rendering menu set
lighting/shading > transfer maps...

Not according to his last response. He wants to bump map.



It's okay though I also thought he was interested in normal mapping at first. The problem is he used every word or phrase associated with every kind of "transfer map" in his original post because he does not know what any of them are so trying to figure out what he really wants is hard!

In any event I have already described both normal and bump maps and even linked to a free tutorial on normal mapping in this post so unless he changes his mind again and wants to do a displacement map (boj moi) he should be covered. ;)

I guess I should take a second and describe the three primary kinds of maps that are used to represent depth.

BUMP: Only requires a grey scale 2D image where 50% grey is no displacement and < 50% grey will appear to be displaced inward and > 50% grey will appear to be displaced outward. Bump does not actually displace the geometry it is only a trick of light and shadow. For this reason bump maps are given away if you get to close to the surface or you view a surface in silhouette.

NORMAL: Uses a RGB image that represents the surface normals of an object. For normal mapping one usually starts with a high-poly mesh and a low-poly mesh and then generates a normal map of the high-poly mesh and bakes the normal map of the high-poly mesh onto the low-poly mesh. Like bump mapping this does not actually displace the geometry it is only a trick of light and shadow. Like bump mapping getting to close or seeing the object in silhouette will give normal mapping away.

DISPLACEMENT: Uses a grey scale map like bump mapping but in this case the geometry is actually displaced. Therefore you can see the displacement in silhouette and if you get close. This can create a large amount of geometry (and dirty geometry at that) and will increase render times significantly but can reduce modeling time and complexity.

Cheers

my bad.... didn't see that post.

hi guys, thanks for all the replys. Prob frustrating not knowing what Im on about.

But CTBRAM showed an example of exactly what Im after.
However instead of drawing the bump in photoshop - this tutorial Im doing actually builds the threads first and then uses them for them to create a new bump map file - thus enabling him to delete the detailed polygon threads and just have a nice detailed bump.

He places a plane under the spread out threads and creates two obj files for each - like normal mapping I guess, but creates a nice bump map file in this other program.

Id like to be able to do that within Maya.
sorry for the long drawn out process.
Graham

What you are describing sounds like normal mapping. Taking the detailed hires geometry (modeled tread) and creating a normal map. Then baking the normal map to the lowres geometry.

A normal map is a 256 (8-bit) color map that represent the (x,y,z) coordinates at each point on the surface. Like bump map it does not change the geometry and is simply a trick of light and shadow and is intended to allow you to take the details from a hipoly sculpt and transfer them to a lowpoly model for better animation performance.

A bit off the topic but to shed a bit more light on normal mapping in Maya you can also watch Mike's free tutorial, it might help a bit. I think he includes the bump map info in the normal map for this, not sure though:)

http://simplymaya.com/autodesk-maya-...=156&sub_cat=0