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What's exactly a skinned model?

Last post 08-20-2008 3:09 PM by sachi raj. 9 replies.
  • 02-12-2008 6:29 PM

    What's exactly a skinned model?

    i've tried alot to integrate animations into my XNA game but i couldn't found a good one except that in the skinned model sample but whats a skinned model and how can i create it through 3DS max ?

    thanks

    Ashour
  • 02-12-2008 8:43 PM In reply to

    Re: What's exactly a skinned model?

    Hi,

    You have to search on any 3D modelling forum ;), I can recomend this one: http://forums.cgsociety.org/

    Take a look at the Application Specific (3ds Max) sub-forum, and then in Tutorials.

  • 02-13-2008 2:11 AM In reply to

    Re: What's exactly a skinned model?

    A skinned model is basiclly a model that uses a highlevel component (ex. joints and bones) to alternate the basic components of the mesh (ex. vertices). The verticies is usually weighted to a joint or sometimes more than one to let the joint know how much the joint should affect the vertices bound to that particular joint.

    In other words when you create a skinned mesh you add a controls that contains clusters of vertices and these controls can be modified to alternate your mesh without having to move each and every vertices by hand. And nowadays the 3D engines can handle these controls aka. bones or joints.

    Well unfortunally I can't answer your 3DS max question because I havn't used it for character animation since R3 and than you need to have Character Studio but I think it they have integrated Character Studio now.

  • 02-14-2008 12:37 PM In reply to

    Re: What's exactly a skinned model?

    Yes, a "skinned" model is essentially a model that is controlled by a skeleton. The old-fashioned method of handling animations for a 3D model was to use absolute vertex keys to animate the 3D positions of every point of the model. Unfortunately, this meant that a whole crap-ton of information had to go into the model's animations. With a skinned model, the verticies are weighted to the bones of a skeleton. Their positions are altered dynamically at run-time relative to the positions of the bones and joints. So the only transform information that the engine needs is for the initial weighting, and the current location and rotation of the skeleton's bones.

    The end result is an animation implementation that takes up a lot less file size, and is much more flexible in terms of real-time interaction. The previous standard was hard-coded animation, and would play the same way no matter what. Skeletons constrain the animations more, but also allow for much more freedom in real-time interaction. For instance, skeletons allow for ragdolls, a feature that would not have been possible with vertex-animated models.

    If you want to export a skinned model from 3DSMax, you will almost certainly have to use 3DSMax's character studio features. First you have to create an animation rig to hook your model up to. Then you need to apply a modifier to your model, I believe the modifier is called "physique." 3DSMax comes with a default animation rig that you can resize and tweak to fit the proportions of your model. Edit the rig to fit your model's proportions before you apply the physique modifier. Once the modifier is applied, you will want to go into its options and edit the weighting for all of the verticies in your model. You have to make sure that every vertex is weighted to at least one bone. You will want to spend plenty of time tweaking these weighting settings so that you get good creases at the joints, the shoulder is especially problematic for animations. Once you're weighting is satsifactory, its time to actually animate your model. I'm going to assume that you already know how to do this in 3DSMax.

    For exporting, you will want to export into the .fbx file format. 3DSMax should already have a .fbx exporting option. I'm pretty sure that the format was originally designed by Autodesk. FBX files support skeletal animations, and should export your model, skeleton, animations, and weighting settings properly. After that you just import it into XNA.

  • 07-27-2008 5:42 PM In reply to

    Re: What's exactly a skinned model?

    Hi richard,

    I am starting my project in xna game studio, what i have to do is implement my own 3d human characters in xna and perform basic animations progressing to advance animations by using xna framework. I need to do this by programming each and every animation.

    I like your feed back on xna creators forum and find in very helpful, can you please in few lines explain how can you do this project by considering that you are very new in xna framework.

    Also i will appretiate if you would share any tutorial or written material for how to implement characters in xna.

    i will appretiate you feedback.

    thanx.

    cheers.

  • 07-27-2008 8:40 PM In reply to

    Re: What's exactly a skinned model?

    sachi raj:

    I'm not sure what you mean by "implement my own 3d human characters in xna and perform basic animations progressing to advance animations by using xna framework". Does this mean you're writing your models and animations by hand into your code? Not using any 3d modeling program?     

  • 07-27-2008 9:16 PM In reply to

    Re: What's exactly a skinned model?

    thanx for ur reply MasterSlowPoke.

    i mean that i am gonna model the character,rig and skin the character model using 3ds max and then use these models in xna. Then i will gona perform basic character animations like hand movement, head movement, walk cycle, standing pose etc then i am gonna perform advance animations like running, jumping, rolling etc. But i don't know how to control the character animation in xna. I only know that xna only takes objects with extension .x or .fbx, thats it. I have worked on a project in making of a game prototype for windows using xna but that didn't include any character.

    cutting it short, i don't know which libraries in xna helps you to animate character. Well it might sound childish to you but i am completely un familiar with the character implementation and animation process in xna. I am trying to find a book or any written material which can help me to achieve this process but didn't find anything after searching for many weeks now.

    Can you please give me some suggestions.

    thanx

    cheers.

  • 07-28-2008 10:35 PM In reply to

    Re: What's exactly a skinned model?

    There is no built-in support for animated 3d models in XNA. There are a number of 3rd party libraries that will let you do this, or if you'd like a better understanding of how it works, you can code your own. I've just finished my MD5 importer and I found it to be a great learning experience.

    There are a number of third party libraries out there. The only one I can think of at the moment is XNAnimation, which I think is maintained by someone else who is active on this site.

     


  • 07-29-2008 4:16 PM In reply to

    Re: What's exactly a skinned model?

    have no words to appretiate your response.

    cheers MasterSlowPoke.

  • 08-20-2008 3:09 PM In reply to

    Re: What's exactly a skinned model?

    @Kaine

    well i am just confirming about the process you have mentioned above to export animated character from 3dstudio max. well i have used skinning instead of physique modifier. and i have used a biped rig to animate my model.

    is there any technical issues which i have to tackle before exporting my model.

    cheers.

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