Rigging a cube \\ Help with bones

[neonugget]

Hello Moho wizards, I'm here to ask for your advice.

I'm rigging a cube that can be rotated in perspective both horizonatally and vertically. I have figured that the most sane solution would be to basically only rig the front edge (consult attached image). The closer the front edge is to the side edges, the smaller the side edge becomes and vice versa. Point is, I'm trying to add the main transform position bone and the front edge bone, but when I bind points to the pin bone I can no longer move it. How would one go around rigging this? Are the tutorials on a similiar system that I have going?

Thanks in advance!

[Greenlaw]

Pretty cool! You might also want to look into using a Perspective Warp as described here...

Perspective Warp and Quad warp

In a nutshell: a strictly 4-point quad mesh, aka Perspective Warp, will warp its interior using a true perspective grid.

Note that this differs from a Quad Warp, which does not apply perspective rules.

[Greenlaw]

As for rigging a cube, I'm the wrong person to ask because I would just animate the cube in a 3D program and be done with it. If I really needed it as a vector animation in Moho, I might bring the 3D render into Moho and trace it. (I've done something like this for other objects in the past.)

But some animators have rigged and animated cubes in Moho, notably after Perspective Warp was introduced. I'm pretty sure I've seen examples in the forum, but I can't find them (it's so hard to find anything using the Search bar.)

Hopefully, someone will post a link shortly.

[Greenlaw]

Here's an idea: I think the easiest way to do this in Moho is to create an unfolded box with each square in a separate layer. Optionally, you can add details or imagery to the squares. When you're ready, fold the shapes in 3D space into a Box. Done.

It's not the same as warping polygons in 2D space, but it could be more effective depending on the usage.

[Greenlaw]

Here's a very sloppy example.

First I made the unfolded box...


I originally placed the back side of the box on one of the ends, but then realized it would be easier to keep it in the center and push it back along the z-axis.

Here's the folded version...


There are a couple of things to consider:
1. Depth Sorting>Sort By True Depth should be enabled.
2. The boxes probably shouldn't touch each other. When I turn the box, the render gets a little unpredictable, and I think this is because the slightest shape overlapping is confusing Moho's depth sorting.

I don't have time to test this further, but maybe someone else will want to play with this idea.

If anything, this can be used as a reference for tracing an animated 2D vector cube.

Another approach is to extrude a square into a 3D cube from the Layer Properties window. However, I've never had much luck with this.

[Greenlaw]

Oh, and don't forget that Moho has a Perspective Points tool. In a true 2D approach, this tool can be used to deform a front-facing square into a side square.

So many ways...

[Greenlaw]

I can't put any more time into this, but if I had to rig the above as flat 2D vector art. I'd use Point Bones on each corner. Then, I'd use Animated Layer Order to move the back layers forward as the cube turned.

If the above doesn't help, can you upload a project? As mentioned, I need to get to work now, but maybe another user here can take a look at it.

Good luck!

[neonugget]

I can't put any more time into this, but if I had to rig the above as flat 2D vector art. I'd use Point Bones on each corner. Then, I'd use Animated Layer Order to move the back layers forward as the cube turned.

If the above doesn't help, can you upload a project? As mentioned, I need to get to work now, but maybe another user here can take a look at it.

Good luck!

Big thanks for looking into this, I didn't know about the Quad warp!

My main issue isn't even the logistics of the rig, but the technical side. I think the method I got should hypothetically work, it's just I can't figure out why the bones don't work the way they should, even though it's not even that difficult of a rig
If anyone has the time and dedication to look into it, here's the project file

https://drive.google.com/file/d/1YBkEdP ... sp=sharing

[neonugget]

Big thanks for looking into this, I didn't know about the Quad warp!

My main issue isn't even the logistics of the rig, but the technical side. I think the method I got should hypothetically work, it's just I can't figure out why the bones don't work the way they should, even though it's not even that difficult of a rig
If anyone has the time and dedication to look into it, here's the project file

https://drive.google.com/file/d/1YBkEdP ... sp=sharing

I also realized that the rig doesn't work specifically when i have the pin bone parented to the root bone, but I don't have any idea how to fix this :\

[hayasidist]

this from moho 13.5 (5 years ago)

[synthsin75]

Your file works here. Are you trying it on a frame other than frame zero?

[neonugget]

Your file works here. Are you trying it on a frame other than frame zero?

I checked the file again and the pin bone can't move if I parent it to the root bone both on frame zero and outside of it

[synthsin75]

Your file works here. Are you trying it on a frame other than frame zero?

I checked the file again and the pin bone can't move if I parent it to the root bone both on frame zero and outside of it

Have you tried with the transform bone tool? It won't work using the manipulate bone tool.

[Greenlaw]

this from moho 13.5 (5 years ago)

There we go! Thanks, Paul.