Rojo does not build model pivots correctly when no PrimaryPart is set

[ThoughtSpinnr]

When attempting to build a project file that includes a model saved as a .rbxm with:

1. A pivot point offset from its center
2. No PrimaryPart set

Rojo will not set the pivot point of the model correctly in the resulting .rbxl

Below is a zip file containing a .rbxm which contains 2 identical models that demonstrate the issue. One has a PrimaryPart set and one does not. Inserting this file into studio directly, you'll see 2 identical models. Including it in a rojo build, you'll see 2 identical models with 2 different pivots.

FloatingRock.zip

[LPGhatguy]

Thanks for the report!

I think this issue comes down to Rojo not supporting pivots as well as it should. It should be just a matter of figuring out how they fit into the reflection database. We've been putting this off for a bit because the feature was unstable for a long time, but it sounds like we should prioritize it now.

[kennethloeffler]

@Dekkonot would you be okay if we just hack a Model.NeedsPivotMigration insertion into RojoTree::insert_instance until we address rojo-rbx/rbx-dom#385?

[Dekkonot]

I would be more than okay with that for Rojo 7.4.1. It's important to get it working and we'll have it fixed properly soon enough anyway.

[kennethloeffler]

I would be more than okay with that for Rojo 7.4.1. It's important to get it working and we'll have it fixed properly soon enough anyway.

Should we just put this change on the 7.4.x branch or do we want it on master too? I'd like to square away the rbx-dom issue before 7.5, so I think it should just be on 7.4.x

[Dekkonot]

Just 7.4.x seems fine! Makes it less pressing to fix it too since it won't be code we'll potentially forget.

[kennethloeffler]

This is closed by #865 (I properly linked this issue with the correct keyword in the PR, what are you doing github)