Parenting can be a pain...

[FlorianK]

When I parent an object under another object, I want still to be able to independently rotate the child object. In my scene there is an animated object a RF emitter is parented to. Everything is working fine right to the moment I have this emitter rotated by an expression like t*200. This results in the emitter geometry getting heavily distorted, not rotating around its own pivot anymore but anything else.

And even more. When I parent an object, the objects values for scale, position etc get overridden. I think this must not be, because the child's position needs to be relative to the parent but individual transforms etc must be possible without using strange values inherited from the parent. For example if I want to scale an object slightly larger, I have to unparent it first, scale, then parent again. Sometimes, even that doesn't work...the scale gets changed, but the animation is read from the animation.sd again, overriding all my changes. Now, for the worst part: My changes in scale are still there in the nodes panel after unparenting the object, as numbers. The object itself has its original size.

In my opinion the whole parent <-> child thing in Realflow should be completely overdone, as this is one of the things that can turn a very simple task into a sheer horror.

[FlorianK]

Parenting....I animated a YPos of an object parented to another one. Instead of movement via an expression in Y the result was movement in the object's Z, which happens to be the parent object's Y.

I don't know how awful the underlying code is to fix, but I still have some hopes this might get addressed before Realflow 2050.

[atena]

I'm sorry, just using two cube primitives and parenting them I have the expected behavior for the parenting feature. When I say "expected" I mean the same behavior you get in Maya when you parent one object to other. Of course when you parent an object to another, its transformation gets changed, because now the transformation is related to the parent object and not to the world reference system. This is exactly what Maya does.

Also, very important, when the parent object scale is not the same in the three axis (the scale is not uniform) and you manipulate the child object you will be deforming the child object because the transformation matrix for the child object is not orthonormal anymore. Try this with Maya or any other 3D software and you will see exactly the same behavior.

Because I wasn't able to reproduce what you mention, can you post a simple scene where that is happening? I mean the one where you are using the expression for the child object. I bet that the parent object has not a uniform scale.

Thank you.

[FlorianK]

After losing a couple of hours of work because of Realflow's beautiful partenting intrinsics, I sent you a scene.

Also, when moving the rotate gizmo, on just one axis, the numbers for the other axes are changing....why?

[atena]

I couldn't do anything with the scene, I loaded it but everything seems to be ok. Don't know what I have to do to see the problem.

When you move the child object if that child object has any rotation then its local axis is not aligned with the global axis. That's the explanation. You can always click on the "axis" button at the top bar to switch between "local" and "global" axis. For this situation changing to "global" will allow you to move the child object as you expect.

[CG_Nema]

I know what you're talking about Florian. I tried to make an example of it right now but for some reason I can't reproduce it. Basically sometimes when I try to rotate a child object, it seems to shear it instead, and even worse... if I unparent the node after that happens, it's permanently distorted but it's shear values are still [0.0,0.0,0.0]. I will try to reproduce it again tomorrow so I can show you what he's talking about Louis.

[atena]

Yes, again, as I explained before if you rotate a child object where his parent has a non uniform scale you will have shear. You see the same behavior at least in Maya as far as I know. When unparenting that object you should see some values different from 0.0 in the shear parameter if this is not the case please send me a way to reproduce it so I can fix it.

Thank you very much.

[blueWater]

I agree with the sheering horror that is parenting nodes in RF. Just the other day I wanted to parent an emitter on a piece of animated maya geometery, after rotating the emitter it sheared itself into an ugly mess.

The way Maya and RF handle parent and child object animation is as different as cats and dogs. Although one can make a point that both are animals.

I wonder if center pivots and freeze transforms in maya have anything to do with the problem.
Now that I think about it I have scene using the center pivots and transforms correct and I still get the sheering problem.

[atena]

I would love to have the scene and be able to reproduce the problem. Just make sure you have a uniform scale as I explained before in this thread. If you have non uniform scale then rotations will produce sheer, and this is not a bug, same behavior in all the 3D platforms I'm aware of.