RBD to FBX, is it possible to export from SOP?

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Hi,

I usually do some quick and dirty fractures and simulations with SOPs (using RBD Bullet Solver, PointVelocity, etc.), and I'd like to expot the result in UE4 via RBD to FBX, but it doesn't seem to work (no animation is exported).

The only way to make it work is simulating with DOP. Is there a way to do it with SOPs?

Thanks.
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+1 on this one.

Using H18.5 + RBDsolver SOP and not having any joy with RBD to FBX.



P.
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UPDATE FYI:

Plug it all into Transform pieces and you can then export via RBD_to_FBX!
(source packed geo -> 1st input, RBDSolver.simPoints -> 2nd: template points, source packed geo -> 3rd: rest points)

…not sure if last connection is necessary but it works.

Hope it helps!

P.
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Some further issues with RBD_2_FBX …and perhaps I'm doing something weird with it.

I've now set up transform pieces without an RBD - just some geo and some template points.

This also works but only for position.
As soon as I try to add any orient/scale/pscale attributes RBD_2_FBX breaks, even if TransformPieces works.


Is there an easier way to export animated pieces to FBX?





…fixed, the templates need full set of orient/pivot/scale attributes for RBD_2_FBX to work.
AND SCALE CAN'T be ZERO

I spent a solid hour trying to figure it out and then find a solution seconds after I post the question!
This forum is very cathardic.
Edited by Piotr Stopniak - Nov. 1, 2020 02:46:00
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Hey!

As of the last production build of 18.0 you can now also export animated RBD pieces directly from sops using the ROP FBX output sop. Just make sure you enable the “Build Hierarchy from Path Attribute” checkbox, and that your path attribute on your RBD pieces are
correct. We will soon be deprecating the RBDtoFBX rop in favor of this workflow.
Paul Ambrosiussen
Technical Artist - SideFXLabs
twitter.com/ambrosiussen_p
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Thanks Paul!

That's a huge help, will test out.



P.
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Hello all ! Any luck with this path attributes and RBD animation exporting via rop FBX ? I've tried to export simple falling object, but in Unity i cannot see any motion at all. How to set up everything properly ?
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I also had problems with this, and it looks like piotr above here has the solution. Add an assemble node after the rbd bullet solver (uncheck rename), and then use a transform pieces node. The first pin should go from the assemble, and the points you can get from the rbd bullet solver (simulation points). The rest input I could leave empty.
This creates a correct path attribute which can be used by the rop fbx.
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I recently ran into a bunch of issues with this myself so here's a quick guide I threw together that might be of help.

In short:
  • Sim with packed geo (or as mentioned above, convert to packed geo using transform pieces)
  • Use the ROP FBX Output in sops, don't bother with the labs RBD to FBX ROP
  • Turn on “build heirarchy from path” on the FBX Output
  • All intrinsic pivots should be zero (this shouldn't be an issue for rbd, but is important for other types of animation)

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kjetil_RTG, pixelninja Thank you very much guys for answering in detail, you're the best ! Now everything is clear and working.
Edited by iceBar0n - Nov. 13, 2020 09:12:09
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ok guys… riddle me this!


I have:
simple packed object -> copyToPoints (with scale,and orient attrs on src geo) ->-> FBX export

WON'T WORK IN UNITY, Maya reports NaN on rotation and SOME channels (like ty)

BUT -
packed geo -> copyAndTransform in place xN -> copyAttrs from source geo pts (rot as euler, scale, P) -> primitive node -> do transform and apply the above ->-> FBX export

EXPORT WORKS!

Comparing the two methods, on the node I'm writing out I can't spot any difference - the intrinsic transform etc seems the same?
is there some other magic that the copy to points does that breaks the thing?



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Does the pscale or scale ever hit zero?
Because I do know that can really mess with the transform matrix. I had some issues with that in unreal.
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I checked that and yes it did.. but I'm pretty sure I tested without as well.

the thing is - using the primitive node to do the transforms applies the exact same scale values and it works!


P.
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Interesting. I did a quick test using copy to points with animated pscale and orient and it worked fine with Unreal (I don't have an install of Unity at the moment to test that).
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I'm keen to spend more time with unreal… getting real tired of unity's BS!
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I personally still prefer Unity. C# scripts feel way more intuitive to me than blueprints or C++.
That's probably also because I've spent more time with Unity. I still have no idea what I'm doing in Unreal haha.
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