Question about Constraint

[hymwan5-c]

I'm new to Maya and have started learning about rigging. Here I would like to select the NURB first (white high-lighted) and soft-select the edge on the cube (orange high-lighted) and create a scale constraint between them. The NURB will act as a scaling controller to scale up and down the targeted edge (expand and squish the cube).

However, when I'm gonna work it out, Maya says // Error: line 0: Target cubeShape not valid. Targets must be of type transform.

If I get this situation correctly, Maya seems only allows us to constrain something to the whole object but not the faces, edges, or vertexes. Is there any other way to get my plan done? Thanks for your attention~~

 (Expected Outcome Simulation) 

[Baboonian]

You need a cluster

[Kahylan · Accepted solution]

Hi!

You are understanding correctly. Constraints only work on objects not on selections.

There are actually many ways to achieve what you want. Generally speaking when you need to deform part of an object, you need a "Deformer" object to do so (you'll find most of them in the "Deform" Menu) The question is, are you aiming for versatility in the Setup or are you aiming for just this effect with as simple as possible of a setup.

If you just want to be able to scale the controller and get this bloating/squishing effect, the easiest way to approach it is a Blendshape Deformer. Using the Following steps:

1) Duplicate your Cube

2) Model the duplicate so it looks like the desired outcome

3) Select the duplicate first, then the original and use the Deform-> Blendshape command.

4) Use a set Driven Key (Animation Toolset, Key ->Set Driven Key -> Set...) to connect the scale of the controller to the target weight of the blendshape. You might need to look up a tutorial on how to do this.

If you are aiming for your setup to be as versatile as possible, you should probably use a joint based rig.

This needs quite a few more steps than a Blendshape based setup, so I attached a short video that shows how I would do it.

I hope this helps!

[hymwan5-c]

Your guide is clear and really helps! I try following the video you take and succeed to make a joint based rigged model. The attachment is a demo animation I have recorded. Thank you very kindly~~