FBX export with Constraints

[Anonymous]

I have an eyeball mesh with an Orient Constraint to a bone. When I rotate the bone, the eyeball rotates as I want. I can export the scene as an FBX with the Constraint box checked and get no errors. However, when I open that FBX in Maya LT my eyeball constraint is no longer in the outliner and the eyeball does not rotate with the bone. 

Maya LT documentation states that the FBX can export Orient Constraints when the box is checked. I have searched the forums and only find other people having the same issue. 

Does the FBX export with Constraint feature actually work? And if so what is the proper settings to get it to work because I can't seem to find the trick.

[Anonymous]

As a follow up:

I realized that the Constraint Box in the FBX exporter only is checkable when exporting an Animation as well. Testing this, it appears to me that the Constraint option in the FBX exporter doesn't do anything as even exporting with an animation loses the constraint within the FBX file. The only thing I can get to work is keying the bone for animation, then using the options Animation and Bake Animation in the FBX exporter. This provides an FBX file with the eyeball following the original bone rotations. However, the constraint for rotation is gone. 

If anyone has any other documentation or explanations on what that Constraint checkbox actually does, and if its possible to export an FBX with contraints inside it, it would be much appreciated.

Thank you in advance.

[sean.heasley]

Hi @Anonymous 

Are you exporting from LT and re importing in to LT or are you exporting from a different Maya version?

Also what version of LT are you working with? This was a known issue with older versions of Maya and I believe has been fixed with our more recent releases.

[sean.heasley]

Hi @Anonymous 

Just wanted to check in to see how things were going. Are you still having this issue?

If your issue is resolved, please click Accept as Solution on the posts that helped you so others in the community can find them easily.

[Anonymous]

Hello,

Yes I am exporting from Maya LT tand reopening in Maya LT.

I am using version LT 2019.

The problem is easily repeatable. 

Just place a cube, add a joint, then Contrain the Cube to the Joints rotation. Export as FBX and reopen with LT and it the constraint will be gone.

Regards,

Arne

[sean.heasley]

Hi @Anonymous 

Thanks for the repro steps!

The "Include Constraints" option is only enabled when exporting/saving as a .MA or .MB file which I just tested to make sure and indeed works. If you export as an FBX the include constraints option will not be recognized. This applies to LT as well as standard Maya.

[Anonymous]

As I understand it, Maya LT files cannot be saved as .ma or .mb files,
correct?

Regards,
Arne

[sean.heasley · Accepted solution]

Hi @Anonymous 

Ah you're right I forgot about that.

This may indeed be an issue specifically with LT so I went ahead and logged this with development so they can either let us know if we're missing something and/or if it is indeed an issue that needs to be fixed.

[Anonymous]

Ohk. Thank you.

For more context. I am making a single skeleton that I plan on using for multiple characters, and using the Constraints would make it so I could reuse animations among all my characters even if their eyes are at different positions. I am using the characters for a video game based in Unity. 

[sean.heasley · Accepted solution]

Hi @Anonymous 

Just to update the devs have confirmed this issue and are working on a fix for a future release/update of Maya.

That said we did notice that exporting the constraint as a .LT file does work and should maintain the constraint if that helps at all for your pipeline when you aren't going into Unity.

[Anonymous]

Hey Sean,

Was wondering if there are any updates on a release date for this?

All my workflow pipes into Unity.

Regards,
Andy

[kirbysteele]

I just found this thread because I'm having the same issue with disappearing constraints. The simple test I'm doing is making two spheres and constraining one to the other. I then export the file as an FBX with the constraints option active. When I import he FBX back into Maya the constraint is gone. I have repeated the issue on different machines and in 2018 and 2019. Is there something I'm missing, or has this been logged as a bug in Maya yet?

[Anonymous]

Hey Kirby,

I haven't tested this in a while so I don't know if they fixed it. I was using Maya LT. It appeared the only way to get the constraints to stick is to use a .ma or .mb Maya file in your pipeline as the constraint is lost in the FBX export. 

Hopefully you can use those in the mean time?

-Arne

[kirbysteele]

Hey Arne,

Thanks for the quick reply. My models are going to Unity so I've been using the FBX format by habit and all my scripts are designed to use that export option. I know they added in .ma and .mb support in Unity, but I haven't looked into the stability or the file size of this approach. Having constraints seems like a pretty useful feature for any file type that claims to support animation, so I'm surprised that this bug is in Maya or the solution is more widely known. In the mean time, I added a step in my export script to do a direct parent to whatever joint the mesh was constrained. The downside is that the joint hierarchy isn't clean in the FBX in unity. Hopefully this gets solve soon.

-Kirby

[nelsoncruz]

Hey,  The issue may simply be how the file is being imported back into Maya. The constraint data is indeed being saved when the FBX is exported out from Maya, we can see it if one reads the ascii itself.
example:
ObjectType: "Constraint" {
Count: 1
PropertyTemplate: "FbxConstraintParent" {
Properties70: {

This file loaded just fine with the FBX constraint intact into MotionBuilder.  
It looks like Maya file load is not saving or reading a preference when a FBX is first being loaded back into Maya.  I have not  fully investigated enough to find the root cause of that but if one does a file > import and select FBX from the file type will be enough to trigger something and make everything work.  From here a normal file > Open will also work. 

Attached a GIF for viewing. 

[Anonymous]

Thanks Sir,I was having same issue in maya 2020 i exported it as .ma file and it works 

[Luis_77]

This works for maya but how to do it for unity?? the constraints disappear 

[Luis_77]

my only option is to animate the bones directly instead of using constraints but that is disgusting

[kqxsonline88]

https://kqxs-online.com/ cung cấp tin tức mới nhất về xổ số từ nguồn tin chính thống.
#ketquaxoso #xổsốtiềngiangkiêngiang #cầudengàymai

TRANG WEB:

https://www.youtube.com/@KqxsOnline88/
https://twitter.com/KqxsOnline88/
https://www.flickr.com/people/kqxsonline88/
https://www.pinterest.com/kqxsonline88/
https://www.reddit.com/user/kqxsonline88/

[providentecopolitenapartment]

Good Blog