Skeleton displacement

# 1 08-06-2003 , 12:33 AM

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I have problem with my skeleton and its attached object. When I move my object, the skeleton moves as well, but in the opposite direction. This would not be a big problem, since the visible object still animates the way I want to. But when I try to move my object too far away, it becomes very difficult to find the right position since the skeleton moves further away from my object. Does anyone know what I've done wrong here?

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# 2 08-06-2003 , 12:41 AM

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Once you attach your skin(s) to a skelton you should begin moving the main skeleton joint instead of your object. You should be able to select a single joint in your skeleton, which will select all other joints when you do select it. You need to move this joint when you're wanting to move the entire object. Hope that helps.

www.Darkware3D.com

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# 3 08-06-2003 , 02:25 AM

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Try Freeze Transformations on both objects before attaching.
Hope it helps,

adldesigner
Caracas, Venezuela
Hell .. not gone perse, but with a certainly lower post count per day.

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# 4 08-06-2003 , 08:27 AM

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Thanks for trying to help me. I think I can explain the problem a bit clearer now. I remade the skeleton and attached it to my object again. When I move the root joint, the skin goes with it, but much further. All transformations I do on the root joint have too much effect on the skin. Please see the picture to understand what I mean.
Can the problem be that I am using a PolyToSubdiv as skin?

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# 5 08-06-2003 , 08:28 AM

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Picture

...and here's the picture to explain it.

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# 6 08-06-2003 , 09:08 AM

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This is because You should only bind the low poly object as skin. As far as I can see, it looks like you have bound bothe the subD surface and the lowpoly to the skeleton.

The lowpoly object drives the highres object, so when you move your skeleton, the skeleton moves the low poly object that moves the highres object and you get what is called double transformation.

I hope it helps you, and I hope you understand my explanation

Carsten Lind
Senior 3D Artist,
Maya Software Manager & Maya Instructor
LEGO Systems A/S

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# 7 08-06-2003 , 09:50 AM

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As far as I can see, the skin only consists of one object: the PolyToSubDiv-object. This is the object I bind to the skeleton. I can't find any object in the Outliner which corresponds to the lowpoly-object in your description. Still, by looking at the picture it's quite obvious that I have two objects; one lowres-object which follows my skeleton, and one highres-object which "overreacts" to changes in the skeletons position.

Is there any way I could show both these objects in the Outliner, so that I can follow your advice and only bind the lowpoly-object?

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# 8 08-06-2003 , 01:41 PM

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Caligraphics is right about the double transformations. When I had this problem a few months back it had to do with way I had parented several objects. Can you take a snapshot of your outliner or better yet, upload the .mb file?

www.Darkware3D.com

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# 9 08-06-2003 , 01:59 PM

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Yes, What Caligraphics says about double transformations makes sense. Still, I'm too unexperienced to find out where I went wrong. I've attached a stripped version of the .mb-file which still has this problem. The root-joint is called 'jNyckelben'.

Thank you very much for taking your time to help me out.

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help.mb (524.3 KB, 232 views)

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# 10 08-06-2003 , 08:47 PM

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I think it has something to do with the polyToSubd operation that you did on the mesh. The smooth skinning is being applied to both the poly object and the resulting subd object, and that yields the double transform. If you select the mesh and look at the channel box, you'll see 2 shape items: polyToSubd... and Turtle2_polyToSubd... (names are too long type out, and I'm lazy). Somehow, you have 2 shape nodes on there, and I'm not sure how you did that. You migh have converted the poly to subd incorrectly or .... something.

There are a couple of solutions. One is to simply "turn off" the influence of one of the skin clusters. Select the root joint, select skinCluster1 in the channel box, and set the envelope to 0. That basically disables any influence that node has on anything.

The other option, which is much cleaner, is collapsing the subd hierarchy. You can do that by going to Subdiv Surfaces > Collapse History. That will create a new subd object without the low-res poly cage, but it will be a clean object and should skin correctly.

Danny Ngan
Animator | Amaze Entertainment
my website | my blog | my job

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# 11 08-06-2003 , 08:56 PM

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Here's what he did: He had the sub-d in "polygon" mode when he bound it to the skelton. Here is another fix. Unbind the object from the skelton, delete history, then rebind. The only drawback is that you'll have to look at the poly box thing around your object while in perspective view. It won't render out that way.

Just remember to right-click your sub-d's and make sure they're in regular object mode before you bind them.

www.Darkware3D.com

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# 12 08-06-2003 , 09:02 PM

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Thank you sooo very much. Now I have a new clean subdiv which works perfectly. Also, I believe I learned something about how Shapes works.

Thank you Danny and all others who have tried to help me. Really inspires me to try to help others as soon as I get some skills to share.

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