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I have a scene with the cloth simulation, turned into shape key animation, using this method: http://blenderartists.org/forum/showthread.php?387461-Bake-Cloth-to-game-engine

How to export the scene correctly and what format should I choose to be able to open this scene in any 3D editor, like Maya or Houdini?


Here is a simplified scene, I tried to import into Maya:

enter image description here Download link: http://www.mediafire.com/download/5bm1jwe6iah5zo0/ClothesOnTheRope_ShapeKeys.blend


I tested different formats:

FBX - after import, objects in the scene are huge, and, the most important, - static:

enter image description here

OBJ - creates a sequence of files, I don't know how to import it, and I need to have a single file with the scene.

enter image description here

DAE (Collada) - after import, I see a huge static objects, with offset from each other

enter image description here

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    $\begingroup$ You should use the .mdd file format. It's exactly for this purpose. You can import .mdd into Houdini from version 9.5. $\endgroup$ – Jaroslav Jerryno Novotny Dec 16 '15 at 17:39
  • $\begingroup$ @Jerryno It would be great, because I already have mdd files for all objects, since they help me to bake cloth animation into shape keys. Do you know how to import mdd in Maya? I worked in Maya a long time ago, and I don't remember anything, and I will be very grateful for the help, and an explanation step by step, if possible. I have to send this work as soon as possible. Thank you very much in advance! $\endgroup$ – Rumata Dec 16 '15 at 17:48
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    $\begingroup$ You have to have an addon to import .mdd into Maya. You can import into Houdini, export as alembic and then you basically have what you asked. Another route would be to export from Blender as pointcloud .pc2 and convert to Maya's .mc maya cache file format. You do that with a MEL script cacheFile -pc2 1 -pcf "c:/input.pc2" -f "mayaCache2" -dir "c:/" -format "OneFile"; just change the file paths. $\endgroup$ – Jaroslav Jerryno Novotny Dec 16 '15 at 19:33
  • $\begingroup$ @Jerryno Thank you very much! I think, , I'll try first the method with Houdini. I've never worked with Houdini before, should I first import into obj file with the static objects in the first frame of the animation, and then somehow to connectmdd file to them (how?), or I can just import the mdd file into an empty scene? $\endgroup$ – Rumata Dec 16 '15 at 20:47
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    $\begingroup$ Yes you need also the static .obj of the mesh on first frame. The .mdd is only the vertex animation. In Houdini you attach the .mdd to the mesh/object. Yes the alembic cache fully substitutes the .mdd files, it's just a more modern file format which can do what .mdd can and more. $\endgroup$ – Jaroslav Jerryno Novotny Dec 16 '15 at 20:57
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How to export the scene correctly and what format should I choose to be able to open this scene in any 3D editor, like Maya or Houdini?

What you need is the .abc Alembic file format which is a production standard. Blender does not support it as of 2.76b but it is planned for some future release.

There are also other formats (.FBX, .PC2, .DAE, .OBJ sequence) how to transfer animations but they are pipeline/software specific - will not be as general as Alembic. But they should be tried first anyway.

We will care only about the final vertex animation - which is general for armature deforms, cloth, soft-body simulations, rigid-bodies etc. The vertex count needs to be constant - it won't work on particles. We will use .MDD NewTek's Point Cache with a static .OBJ to export the animation out of Blender into Houdini.

In UserPreferences under Addon in section Import/Export make sure .mdd and .obj are enabled. Go to first frame of your animation and export your object as .obj and export the animation range you want as a .mdd vertex animation. Blender has Z as up, Houdini has Y up, also keep vertex order pls:

enter image description here

If you don't have Houdini then download it for free (Apprentice licence). There is also an Indie licence for $200.

Inside Houdini Import your .OBJ with File > Import > Geometry. Almost everything is done there inside a Node window. Double-click your object node to enter it (you will see a mesh node inside) and hit Tab to invoke a new node menu. Select Import > MDD and connect it below your mesh node. Select the new node and import the .mdd file into it:

enter image description here

The yellow black crosshatch around the node should disappear. Click the blue eye icon of that mdd node to view it's results and play the animation.

To export this animation into Alembic we will use another node to render the animation into a file. Jump back to object level with AltLeft Arrow and add a ROP node (Tab > Managers > ROP Manager). Enter the node (double-click on it) and add a Alembic node (Tab > Scene > Alembic). Select the node, set it's parametres (file path, change from single-frame to frame-range) and render the animation into a file.


Getting animations into Maya can be also done as exporting a .PC2 PointCloud and converting inside Maya to .MC Maya Cache file format. You do this with a MEL script:

cacheFile -pc2 1 -pcf "C:/input.pc2" -f "mayaCache2" -dir "C:/" -format "OneFile";

Just change the file paths.

Then you import the .MC file inside Maya.

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