Geometry Cache / polySmooth node problems

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  04 April 2007
Geometry Cache / polySmooth node problems

Hey All,

I am using Maya 8.5 geometry cache feature to cache out animations on our characters. I then reassemble a “clean” scene, import our character’s main model (without any rig), and import the geometry cache. The cache works fine but it seems to disconnect the polySmoothFace node I have on my characters. After the cache is applied, the Divisions will not work anymore.

The work-around is just to reapply the smooth node after the cache import, but I am curious to why this is happening…. Does the cache disregard the history on the model?

Any feedback would be greatly appreciated.


  04 April 2007
The cache file reads the vector information provided for the number of vertices that were cached at the given point of the geo cache. If you smooth before you re-import the cache file, it will disregard the polySmooth because the XML header only reads the given number of vertices cached before the smooth.

If you know that you need to smooth the model, I'd suggest doing so and deleting non-deformer history before passing the mesh off to the baking to assure you're getting solid results. That's the process I've been using here and coded into our pipeline.

  04 April 2007
Hey Shawn thanks for your feedback/workaround. So here is another geo cache issue…..

What is the historySwitchSet node? It seems to be created at the time I import geo cache and it tends to disconnect my characters textures. Sometimes my textures disconnect right away after cache import or it's disconnected after I save and re-open the file. Could this historySwitchSet node have anything to do with it?

Sucks because I have alot of characters and over 50 shots to take care of.... :( Any thoughts why this would happen?

Thanks in advance,


Last edited by superMijo : 04 April 2007 at 02:13 AM.
  04 April 2007
So I found on the tech support forum at Autodesk that other people have the same issue of UVs getting disabled after saving a file that has geo cache. Their workaround suggested is to: connectAttr pPlaneShape1Orig.worldMesh[0] cacheSwitch1.undeformedGeometry[0]; This workaround is very inconsistent and according to the site “A fix for this bug is currently being investigated and may be addressed, in whole or in part, in the subsequent Update or Upgrade release.” That posting was for Maya 8 and I am using 8.5

So my questions to you character setup guru’s are:

Has anybody found a more stable workaround for this issue?

Or what is an optimal workflow to transfer character animation from animators to the rest of the pipeline (IE. lighting, fx, and especially rendering), with little to no rigs or controls.

Suggestions, comments, questions, & feedback are totally welcomed!


  04 April 2007
Hey Ernie,

I completely understand your problems because that's exactly what we ran into here when I first started the baking pipeline. The workaround I created was we publish 'still' models which is just the geometry with shaders and textures applied to it, no rig, no blendshapes or anything fancy like that.

The process was as follows:

-> animation passes the file to baking
-> all creatures get baked and cache is saved to the network
-> script reads the references inside of the anim file and adds them to a CreatureNode created in the scene.
-> CreatureNode contains attributes which stores paths to the creatures 'still' model
-> script loads a fresh new scene and parses the attributes from the CreatureNode, importing all of the required still models.
-> script re-applies the geometry cache to the 'still' models geometry and then the scene gets passed off to lighting with only geometry, cameras and layout left in the scene.

Manually, this is also a pretty easy step as well and I've had to do it on one of our other features in-house just due to time constraints. Here's the manual workflow:

-> create geometry cache on the creatures using either Single Cache File or Cache Per Frame (there's a 2gb write limit out of Maya and a 20,000 character limit for text files when writing to XML's from Maya so if you go beyond this with complex scenes, Maya will error out and give you an invalid cache file).
-> delete the rig hierarchy, get rid of any low resolution proxy geometry leftover.
-> clean up the scene of any extra junk and import any cameras/layouts from references.
-> pass the scene onto lighting/vfx/render.

For the historySwitch node, that is simply there to control the cross-over between your deformers such as your skinCluster and your actual caching.

A few things to be aware of when using geometry caching:

-> all geometry MUST be frozen, any transforms either on a parent node or the geo itself will result in the geometry inheriting an offset transform when the cache is applied.
-> There cannot be any history left on the model, it should be as clean as possible when the cache is on.
-> always save the cache file into a maya ascii file, it's easier to prune and edit should anything become unstable.

As for the UV issue, I've yet to have any problems with UV's disappearing on any of our models and I've been using the 8.0 caching system for a while with a few extra tools I wrote ontop.

Let me know if any of this works for you or fixes anything, if not drop me a PM or post back and I'll see what I can do to help alleviate some stress off you

  04 April 2007
Hey Shawn,

Damn! Thanks man for taking the time to breakdown your workflow. I really appreciate it. I will go through your process and see what I come up with. The whole UV thing doesn’t happen every time, but it does happen and it's frustrating. This process is similar to what I am trying to do, but I see the areas that I need to pay more attention to. So thanks for the clarification.

I’ll give it a shot and let you know what happens. Thanks again!

  05 May 2007
Geometry cache with uv set locked

Hi Guys,

I'm encountering such uv problem recently. I searched Autodesk's page but clicking the links it shows nothing. Does it requires the platinum login ? Does it already solved anyway ?

  05 May 2007
Yeah, I guess you need platinum support. I have talked to them and it is still a known issue and all they can offer is to submit it as a bug report again. They are not sure when it will be addressed.

So, what I did to workaround this issue is to save out the uv/texture info of the character, either copy what MEL is doing when you assign textures to faces, or in our case due to the multitude of characters, we have a script that writes out txt files of that info and reassigns it later on after the cache has been applied.

Apply the cache to the character and then run your script. Hope this helps out!

  05 May 2007
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