Hello All,

How would you import robotic models for animating in Houdini?

In my case, I have a simple robot model from Maya. What I have done was to separate each moving part into their own groups and export them each into different OBJ files, like head.obj, L_upper_arm.obj, R_lower_arm.obj…etc.. Once I imported all, I adjusted the pivots for each of the parts and start animating from there.

For me, I really thought that I should have all the parts inside Geometry level and animate there but I just can't find a way to do from importing menu. Of course, I could cut and paste all of the file nodes into one single Geo node and merge them together and animate inside Geometry level. But does that make sense for animating robotic models?

Do you animate them in Scene level or Geometry level? What would you do differently?

Sincerely,

David

Hi David,
Keeping all the parts seperate is the way to go but do remember to zero out all your transforms in Maya. You are in effect making a tree of parts. Import into Houdini. What I would do next is build a simple scene structure so you can then version up your robot assets from disk. ie you make an adjustment in maya and then seamlessly in Houdini move a slider and version up . Normally animation is done at the object level not the sop level foir rigged characters.


Rob

Thanks for confirming with me, Rob!

Question about the scene structure. By saying “move a slider and version up,” do you mean everything including exporting the new OBJ file, replacing, and then letting Houdini to reloaded…etc.?

I really would like to learn if there is any efficient way of doing any task in Houdini so please share with me if there is any. The slider way really sounds nice. D

Thanks,

David

version up > just a simple set up to read the next version of the geometry off disk.
ie myrobot_v001_.obj sits on disk. In houdini adjust the file path with a simple slider that alters the “001” part of the file path. That way you can control what version of the geo you want to load from disk.

Rob

I am not sure how to customize it inside File node yet but totally understand the idea of it, I will look into it.

That would be really efficient and also “procedural,” isn't it?

Thanks again, Rob!

circusmonkey is talking about when you save your pieces from Maya to have a naming convention where the version number is in the file name. So when you refer to it with the File SOP all you have to do is change one digit.

ie v001 > v002

You could even store the file version in a variable ie $VNUM. So in your file sop is would refer to model_part_etc_$VNUM.obj and by changing the value of $VNUM it would automatically adjust all the other File SOPS.

Why do we do this ? you may ask. Its so in Houdini you can build a structure of nodes that allows the data to flow with ease. Imagine doing a file > import > FBX everytime someone in the modelling department made an update, it would get very tiresome and messey as often you might want to extract and alter some parts of the model. THis work flow is something Maya users can only dream about …………

Rob

Thanks a lot, circusmonkey and phrenzy84!

I have a feeling that there is something we can add to set up an integer slider inside Edit Parameter Interface Window. But still don't know how to link them to work. Or maybe I am wrong, haha.

For now, I will have what you guys suggested to save model files in version numbers and just change digit as I go.

Learning a lot from you guys! Thanks!


Sincerely,

David