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View Full Version : Skinning a machine/mech...


davidfro
01-17-2006, 03:14 AM
I've never quite understood what you need to do different when setting up the skeleton and binding a machine/mech. What do you need to do different to make it work? do you group a set of parts together that are supposed to move together and then skin the sets of groups? What is the best way to do this? Any suggestions are greatly appreciated.

Davido Hyer

Me109
01-17-2006, 11:34 AM
Well I guess first its best to understand that skinning is exactly for that, making a 'skin' out of something. So a mesh object becomes flexy around a joint area of two bones.. Sure you can use this for Mechanical stuff.. but mechanical armatures and pivots are strictly rigid and have no skin like behaviours..

So you could just simply parent each part of the mesh to the framework skeleton. No skinning involved, which means a real nice high speed rig (no evaluation of a skinned mesh).

Using the skinning option works well too, replacing the perhaps tedious task of individually parenting each mesh to a bone with one simple operation. Except that afterwards you might have to remove the unwanted influences from bones, so you rigid mechanical parts don't deform like a 'skin'.

However with skinning you can use the option to bind to selected joints, which is great because you don't have muck around with parenting, or removing unwanted bone influences later..

Anyhow hope that helps

malcolmTG
01-18-2006, 08:09 PM
unless there is some pipeline specific reasoning for skinning i try to avoid it as much as possible with mechanical objects. you just end up having slower evaluation becase its calculating on a vert level as opposed to an object level as with parenting or constraining. and personally i prefer to constrain objects because i like to have a more disjointed hierarchy that allows for easier manipulation than you can achieve through a hierarchy of objects parented to control parented to bones and so forth.

davidfro
01-18-2006, 08:47 PM
malcom, thanks for the suggestion. I'm not exactly sure what the method you explained is. If you don't use bones, how would you set up a machine using this method? Could you post an example scene, or write out the basic workflow for doing this? Thanks a bunch.

Davido Hyer

malcolmTG
01-19-2006, 04:33 PM
well the only reasons to use bones are for skinning of for an ik system. so if you setup your hierarchy to be just the controls than you can parent the mech pieces to the controls or constrain to the controls.

when i mentioned a disjointed hierarchy i meant having all the bones under one group, all the controls under another, and the meshes under another group. all the interconnections between them are done using constraints. the reason for this is that if a control needs to be moved or zeroed out then you dont have to worry about rebuilding a hierarchy. if you have bones parented to controls parented to bones and so on up a hierarchy then you have a nightmare when you need something to be changed around.

peace.
malcolm.

stoffe
01-19-2006, 04:43 PM
parent a part of youre geometry "the toes to the foot to the ankle etc" and work the parenting upwards then u simply parent the geometry to the joints.

yenvalmar
01-28-2006, 02:26 AM
its exactly how i am doing it on this, except i'm parenting the geometry to my skeleton cause i'm lazy like that. but the skeleton is dreven by an entirely separate control rig using constraints.

this shows the control rig

http://www.yenvalmar.com/nonprofit/theory/karma/images/wingrig_v14.avi\ (http://www.yenvalmar.com/nonprofit/theory/karma/images/wingrig_v14.avi)

here is just the geo

http://www.yenvalmar.com/nonprofit/theory/karma/images/wingrig_v15.avi

any tips on mirroring complex rigs like this? i found i had to separately mirror my geometry, skeleton, and control rig, then re do all the constraints... which is why i used parenting the geo, because if you duplicate the entire heirarchy it copies your geometry at the same times, and saves a lot of time as i have quite a few pieces.. but i can find no way to mirror the whole shebang.. having to re do the constraints and IK was a time consuming chore. yay. :)

it might seem like a lot of extra work to do a really contained separate control rig, but it will save your butt so many times once you start animating and have to change the setup and model, to not lose all your animation data with mesh changes and vica versa

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