View Full Version : Question for Bernard: using weightmaps

 Zoogie09 September 2004, 03:37 PMHi Bernard, I am going through your production tutorials, In chapter 1/material basics 3, you made a comment about avoiding the use of multiple matierial on an object by mapping them to individual polygons on the object. But suggested using weight maps instead. (in the tut, you said there was a bug in XSI that made the previous method undesirable) My question is , Does this still hold true as of version4?, and which method do you recommend at the moment. thanks
Atyss
09 September 2004, 07:28 AM
Yes I think this still holds true in v4. Now I also recommend it for workflow reason, working with clusters is imho so counter-productive in terms of efficiency....

I still recommend the same approach, that is, using weigth maps (small black and white textures) to blend different materials.

Btw, the 3dtutorial site has a forum at wich you can post questions directly related to the products :)

Cheers
Bernard

francescaluce
09 September 2004, 11:38 AM
working with clusters is imho so counter-productive in terms of efficiency....
I still recommend the same approach, that is, using weigth maps...:scream:

ciao
francesca

Zoogie
09 September 2004, 11:57 AM
THanks Bernard,

I actually forgot about the 3dtutorial forum.

Your lessons are very well thought out and executed.
Thanks for taking the time to do them.

cheers

Zoogie

RuiFeliciano
09 September 2004, 09:55 PM
Coming from LW and still taking baby steps on texturing in XSI, I'm used to simply select a polygon (or a bunch of them) and applying a material to them..to me there simply can't be a simpler way. In LW there's also the possibility of defining weight maps and blending different surfaces but in LW workflow that's a quite a...mamoothian (sp?) approach to such an easy task as appyling two diferent surfaces to diferent polygons (providing there's no need for a blend between surfaces, in that case indeed a weight map would be the answer).
I'd be very interested in learning why the extra steps of having to define weight maps would help manage the workflow in a more efficient manner in XSI (providing that there's no bugs using that methodology in version 4, of course).

Atyss
09 September 2004, 09:42 AM
Well, the only bug I know of is some flackyness with few mix modes inside the Mix_2colors. As far as mixing with Alpha and Mix modes, it's fine.

Basically the point of using masks is to have only one material per object to manage, and optionnaly one projection. You unwrap the entire object, for each "island" of UVs you create a very small texture (64x64 should be fine) in wich the island is in white color, while the rest is in black. These will be your marks.

Then you use a Mix_8colors node to blend the various materials together, and plug the mask textures in the weight inputs of the mix node. It's actually very straigthforward, but you will end up with a bigger render tree.

If you have to use only one illumination shader but the object fully covered with textures, you could create one projection per "part" you wish to create. In each projection, unwrap only the part that will have the material, and scale everything else in the bottom left corner. Do that for each projection. After that you need to create only one mask texture, the bottom corner being black and the rest being white. In the Render Tree, you'll have to pick the right projection for each texture.

Cheers
Bernard

francescaluce
09 September 2004, 01:23 PM
ehy !! thanks bernard.. I was waiting for this tecnique.. so let me sum the steps.. you have to use bitmaps, to unwrap the whole mesh, deal with uvs and rendertree.. and you call this an efficent way to get multimats on the object.. are you going crazy or what ??.. :scream:

ciao
francesca

Atyss
09 September 2004, 01:59 PM
.............

RuiFeliciano
09 September 2004, 03:37 PM
Thanks for taking the time to explain your workflow Bernard, I apreciate it.

As I mentioned, coming from LW this represents quite a lot more work to deal with than the way I'm used to (dealing with UVs and weights, etc) just to assign a material to several polygons when no blending is necessary. But I'm learning XSI way of doing things :)

RuiFeliciano
09 September 2004, 03:39 PM
Hi Francescaluce, would you mind elaborating a bit more on your way of doing these kind of things...I wanna learn ya know :)
Do you simply select the polys, slap them with a material and that's it?

francescaluce
09 September 2004, 04:11 PM
Hi Francescaluce, would you mind elaborating a bit more on your way of doing these kind of things..damn.. I donno what the heck remains to elaborate.. as you said.. I simply select the polys and slap them with a material.. what should I do ?! :)

ciao
francesca

RuiFeliciano
09 September 2004, 10:14 PM
thought so but wanted to be sure there was no imported-from-maya shader around ;)

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