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View Full Version : Can blendshapes store normal information?


HowardB
08-12-2005, 10:45 AM
Example. Blending between the default face and a target smile. If the normals donít change when blending, you wonít see the crease on the cheeks. So is there a way to make the normals blend between aswell?

pixade
08-12-2005, 05:05 PM
what i try to do when i do a smile, is puff out/lift up the cheeks with the soft mod tool and sculpt faces tool, that way you will get a crease ..... lighting helps too. that whole normals thing sounds complicated ...

HowardB
08-13-2005, 12:22 AM
Yes. But Iím not talking about how to model blendshapes.



But how to get them to blend the normals. I know that it can be done, because Iíve seen Jason Osipaís face rig he did for his stop staring book do it. I donít understand how he managed to get it working.. Even if you baked out 2 shapes back to geometry and blend between them, they still will blend the normals! Iím thinking thereís some kind of extra information about the normals stored at the vertex level.

Someone please enlighten me!

JasonOsipa
08-13-2005, 05:18 PM
Your problem is with your mesh. You've done something to your normals - by default blendshapes carry normal information, but there are different "normals" tools and steps you can take that break that - and I don't remember all of them :(

Andrei2k
08-13-2005, 06:10 PM
I believe the normals are driven by the edges, faces and verteices not the other way around so in order to smoothly blend from normal to normal your components have to be in a corrent orientation before and after so the blend looks like the normals are smoothly interpolating. But Jason is right your mesh had to be very precisely modeled and set up on base and targets.

HowardB
08-14-2005, 04:55 PM
Your problem is with your mesh. You've done something to your normals - by default blendshapes carry normal information, but there are different "normals" tools and steps you can take that break that - and I don't remember all of them :(


I believe the normals are driver by the edges, faces and verteces not the other way around so in order to smoothly blend from normal to normal your components have to be in a corrent orientation before and after so the blend looks like the normals are smoothly interpolating. But Jason is right your mesh had to be very precisely modeled and set up on base and targets.




I donít know you guys. It sounds like it should easily just blend like you say, but in reality (for me at least) that just doesnít happen. I must have done something wrong I just donít see it yet.


Iíve made a video to show you what I see. LINK (http://bryan-howard.com/Temp/blendshape.mov)


From my understanding my 2 shapes and there normals seem to be correct, thereís no construction history on anything except for the blendshape and as you can see thereís no blending. I could send you this file if you care to take a look, maybe you could tell me what Iíve done wrong.

Andrei2k
08-15-2005, 03:08 AM
It looks like only half of the blending is happening. Is that what you mean? on your blendshape slider im assuming the video shows you moving it to 1 try typing in 2 or 3o to your slider value and see what happens. If I got the problem wrong let me know...

HowardB
08-15-2005, 06:33 PM
yeah thats not the problem. by blending a value more then 1 your over blending the shapes in this case i don't wanna do that. it just looks that way because the normals arn't blending.

like its not a life or death thing if it works or not, because when i put a smooth modifier on top it, it'll resets all the normals anyway. The reason i wanted to get it working on the low poly version is so it represents the final output better for doing the syncing part.

Andrei2k
08-16-2005, 03:45 AM
Ohhh one has a smooth modifier on it......I see well that makes perfect sense. Yeah you cant really see your output from the low poly unless you put a smooth proxy on it so you can see it change as you modify/work and after your happy just duplicate the low poly out and keep doing that until you have them all. But one bing smoothed makes sense with the result you have thats normal because theres a lot more polygns obviously in use so all of them dont move as drastic as your low poly so you have to exaggerate your low poly deform to make the final look right.

HowardB
08-16-2005, 10:51 AM
I donít find that entirely true because Jasonís rig is proof that the low poly blend shapes will blend normals perfectly between your target and base shape irregardless on how soft or hard the normals are in the target shape. The output of his blends (that are on full at 1) will match perfectly to the target shape.


I donít think itís a matter of trying to exaggerate the blendshapes because even if I change the value up to 10 (which totally explode Ďs the mesh) the normals will still stay consistent to that of the base shape, so no normal information being transferred when blending what so ever. The reason that the normals are fixed with the smooth proxy or smooth modifier is because they are being recalculated from scratch because the geometry has changed.

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