Questions about rigging bitmap characters

[ladlon]

Hi. I understand the ways of rigging a bitmap character when each bone gets an isolated bitmap body part (character cut up in each moving part)... as well as how to rig several bones controlling different parts of a single bitmap.

But, what I'm trying to figure out currently, is if and how you can do a mix of those two techniques.

For example, say I have a 2 image layer character... Isolated arms (both on one layer, stretching out to the sides), and the second image layer containing the rest of the body... torso, head, legs). I have the arms separate, so that the body isn't affected by the arm bones (since you can't do the handy 'bind points' with bitmaps, which would have solved that problem).

So, I can easily build a head/torso,legs bone heirarchy and attach it to the 'body' layer... and I can also create a pair of arm bone hierarchies (both in the same bone layer), and attach it to the 'arm' layer.... giving us now two bone layers, each with a single bitmap inside.

However, obviously when the torso is moved, the arms do not follow, since the arm bones are not linked to the torso bone... and I don't see any way to parent the arms (or arm bones) to the torso (or torso bones)... since it SEEMS like bones need to be in the same layer to parent to each other.

Putting everything within ONE bone layer works, but then you face the original problem of having the arm bones pulling at the toros bitmap.

So, I'm wondering if there's some way around it? The only solution I can see, is to break EVERY part of the bitmap into separate pieces (ex. upper and lower arm), and always having only a single bone associated with a single bitmap layer... but then you are basically back to a rigid, hinged puppet, like I was previously using in AfterEffects... and I really would like things like arms/legs to be done with dual bones and image bending/distortion, rather than rigid, separate pieces.

So, I'm wondering if there's some workaround, or feature I am unaware of.

Hope you can help! Thanks.

(Moho 12, PC)

[Greenlaw]

Sorry if I'm misunderstanding-- I'm a bit busy at the moment so I skimmed your post--but it sounds like you want to bind different art layers to specific bones. There are many ways to do this but the most common is to select the layers you want bound first, select the bones, and then choose Use Selected Bones For Flexi-binding. You should repeat that for every separate region of you character. For example, select all the arm layers, select the upper and lower arm bones, then choose the command. Move on to the next binding. Once you've bound all the elements to explicit bones, each part will only be deformed by the bones they belong to.

The key is to bind everything. Any art layers that are not bound to at least one bone will be affected by all bones in the rig, which typically doesn't produce good results.

That's probably the simplest method and explanation but. you can also combine other methods depending on the type of control or deformation you need. Stick with the basics (selective Flexi-binding) first, as they should cover most of your rigging needs.

Since you're specifically asking about binding bitmaps, you should also read up on Smooth Joints. Smooth joints are a pair of bones that's will create a nice clean bend to a single bitmap layer, usually significantly cleaner than a normal bend. I use them at work all the time and they. usually work great even with some heavily textured images. When it doesn't work so well, you'll need to consider creating a custom mesh layer, binding that, and using a Smart Bone action to correct the deformations.

Regarding nesting bone layers within bone layers, I don't recommend that. Unless you have a very good reason for doing this, it's probably just going to complicate animating the character and managing the keyframes.

[ladlon]

Hi, Greenlaw. Thanks for the reply!

Ya, it's still not working for me... I have a regular rig (center spine, going up to head, two legs attached to first (hip) bone, and two arms attached to the chest bone... and three bitmap layers (separate head, body/legs, and arms).

The whole rig works fine, in that it auto assigns all adjacent parts of each bitmap to each nearby bone's influence.

However, the problem is, that the upper arm bones influence the nearby torso areas... which is why I made a separate arm bitmap layer. But, with a standard setup (all bitmap layers inside a single full bone heirarchy layer), the arm bones also influence the torso.

I then tried selecting the arm bitmap layer (constains both arms), and selected ALL the (4) arm bones, and used the menu item Use Selected Bones For Flexi-Binding (as you suggested), but they still influence the torso bitmap layer, rather than just the arm layer (because both bitmap layer are within the Bone layer). Maybe I did something wrong?

The issue basically is... I want the arm bones to ONLY influence the (separate) arm bitmap layer... yet be part off (attached to) the rest of the body bone heirarch (so the arms move with the torso).


Again, if this were vector artwork, I'd simply select just the points within the arm shapes for that bone, so it would have zero influence on the nearby torso... but since it's a bitmap, it doesn't appear I can exclude the body bitmap layer from the arm bones... aside from having a separate arm bone layer that contains just the arm bones and the arm bitmap layer... but then it wouldn't be attached to the rest of the body bone heirarchy.

[ladlon]

(Moments later....)

GOT IT!! Okay, so as you say, the key is to bind EVERYTHING... Initially, I thought you meant just be sure everything is bound by SOME means (including the auto binding resulting from having layers under/inside a bone layer)... but then I specifically did the same 'use selected bones for flexi-binding' on the REST of the body (remaining non-arm parts)... and NOW it works.

Awesome! That's exactly what I was after!

Thanks so much for taking the time to help me out on that. Very much appreciated!

Cheers!

[Greenlaw]

Glad you got that sorted out!

Yeah, rigging can get overwhelming at first because there are so many options and different ways to do it in Moho. When starting out, I suggest sticking to the Flexi-binding options because they're very capable but also generally easy to understand and predictable. But be aware of the other options...as you gain more experience and start working on more sophisticated rigs, you want to explore combining some of the other bone binding techniques for specific situations where Flexi-binding alone isn't enough.