View Full Version : Camera projection in XSI

09 September 2004, 03:15 PM
Just another Q from a non-XSI user thinking of getting Foundation. Regarding camera projecting textures (I think projection texturing is called implicit texturing in XSI as opposed to explicit usage of UV's), does XSI have a way of limiting the texture from projecting through the object and appearing on the back? In other words, a way to ensure that the texture only maps to surfaces that are visible to the camera.
This would allow you to have one camera projection on the front of the geometry, and another on the back, for example.
It sounds obvious, but is hard to set up in Maya.
Also, is it a simple matter to bake these projections?



09 September 2004, 06:20 PM
I think the front-back switch in the rendertree is what you want. Not sure about the baking part.

09 September 2004, 06:19 AM
Thanks, that sounds like it does it. I also see that bodypaint 3D has similar functionality with projection painting that gets baked to UV's, and across groups! Pretty powerful. And I found the BP2XSI plugin. Definitely a powerful option.


Facial Deluxe
09 September 2004, 05:58 AM
I don't know how are the UV in Maya, so I can't compare.
I did several quick camera projection stuff recently for some preview projects, and I found this rather easy to do in XSI.
First, you can throw your camera very aproximatively, set the UV cam projection, freeze UV, and then edit them manualy in In Texture UV editor. This goes very fast, the UV tools are good.
Then, you can move your cam to another point of view, create a second UV cam projection, do the same as mentioned before, and copy/paste the part of the UV you want to the first your projection you created (if this is what you want).
Or, work with several UV projections and blend them via Mix2Color node in the render tree.
Cascading several Mix2Color nodes is easy and very logical, through there are now Texture Layer editor to do this easyly (but I don't use it as I have my habits with Mix2Color)
In Texture UV editor, you can also add "subprojections", though there are no subprojection for camera, you can use some small planar projection for details and place them where needed, you can either move it in the UV view or in 3D view as you can grab and move the projection plan interractively...
From XSI 3.5 to 4 the UV tools have made great improvement, one of the cool thing is the Heal tool that allows you to match/blend several projection : Grab 2 corresponding edges (XSI tells you who matches with who) and Heal tool will kind of weld the selected elements at the same place.

09 September 2004, 09:19 AM
I'm definitely interested in camera mapping for UV layout, but the advantage of using conventional camera projection mapping for say a digital matte shot should be that you can map across groups of objects, and you don't have to layout UV's beforehand. I notice that using projection painting in Bodypaint 2, you can get the best of both worlds though, which looks interesting. ie. you can project and paint across groups, and it gets baked to UV's, assuming you have laid them out already.

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