Bones are good tool and can be very useful and I had some success using them: Practice artwork - #13 by Majkel
But they’re definitely a learning curve and can be so frustrating to work with, I don’t know why but bones can be so broken, it might be just me specifically or other people also might have these problems. I made tests using Synfig 1.5.1-2021.10.21-linux64 and I will update this post with time as I find new bugs.
Anyway
1. GROUP TRANSFORMATION
Here is how bones should work, the blue lines on hand show bones where they actually are. This hand looks pretty good
Now here we see it being broken as hell
This might happen while trying to link vertices inside group to bones, skeleton has to be outside of said group for this to happen
What breaks bones is transforming group hand in any way. Modifying anything
- Origin
- Offset
- Angle
- (Didn’t test but Skew angle probably too)
- Scale
Will cause broken bones, if your bones suddenly get broken don’t fear because there’s fix to that (most likely). Simply set group parameters to original values i.e. Origin, Offset, Angle and Skew angle to 0 and Scale to 1, then you select all child layers in group and move/scale/rotate them to where they need to be.
However it might not work, in project I’m working on I copied leg group and moved it, when bones were broken I set group to default values, moved child layers to where they need to be and bones were still broken AND I DON’T KNOW WHY (EDIT: there was group scaling I didn’t notice).
2. COPYING GROUPS
While having character chopped into groups it is tempting to just copy groups for ease like I did with Orange:
There is head, neck, main body, tail etc. Being lazy I duplicated legs on left side of her body and just changed Z depth, similarly with wing, I made 1 wing and just duplicated it then added bones and everything works and is dandy.
Problem appears when I want second dragon but don’t want to do bones all over again so I duplicate with rigged bones.
There are 2 connected problems that appear simultaneously, first one is (not so) random parts detaching from bones
2nd problem: wtf happened here?
On top of wing detaching from bones it also looks like this
It does look scary but solution is simple. Turns out few bones are named the same
In red frame there are bones from wing (bone 28, 29 and 31) while in blue frame there are leg bones (bone 28, 29 and 30). So obviously having the same name for bones causes problem when duplicating rigged model and solution is to change bone names to something unique before duplicating.
Honestly I don’t even know how this happened in the first place, prevention method would be not being lazy with naming bones but I didn’t want to just change names of 37 bones.
I’m writing this in hopes it will help someone who encounters this problem because it took me so much itme to figure this out. If skeleton layer is inside group that is modified then it works as intended.