I am using blender for 3 months now, and got into animation now.
I am trying to animate a little project for study purposes ;-).
But i get stuck at " constrainting" a piston, how stupid can it be.
The main problem is that my axis are screwed i think. The “track to” constraint gives the part a angle of 45 degrees with my normal axis.
Another questions is . Wouldn’t it be easier when rigging it with bones etc ?
Tank you for reading this and hoping for an answer
Check out this Tut on: CG Cookie
It might have some answers to help.
You can view bone axis and then correct them.
In the same section (animation) on CG Tuts there is an introduction to character rigging, this deals with the topic of axis being misaligned.
A simple 5 bone armature will do, see attached file.
I created an armature with 5 bones. The bone ‘Flipper’ should be selected when you open the file and it controls the action. The bone ‘PistonAnchor’ is a child of the ‘Flipper’ bone and moves as it does. ‘PistonAnchor’ has a child, it’s the ‘Piston’ bone and it follows it’s parent as well. The ‘Piston’ bone, when in pose mode, is green in color because it has a Stretch To constraint on it. To view the constraint, go to the bone constraints panel (in properties panel, it’s header icon is a bone with a chain link by it). It’s target is a bone called ‘CylinderAnchor’. This constraint causes the bone to (as it’s name implies) Stretch To it’s target, ‘CylinderAnchor’.
‘CylinderAnchor’ is off by itself without a parent, but it has a child bone, ‘Cylinder’, and stays connected to it. The ‘Cylinder’ bone is green in color in pose mode because it has a Track To constraint on it. It’s target is the ‘PistonAnchor’ bone, causing this bone to always Track To the target.
So the two green bones, in pose mode, are both tracking each other’s parent. The ‘Cylinder’ Tracks To the ‘PistonAnchor’ so it always points in that direction. The ‘Piston’ bone with it’s Stretch To constraint is always trying to it’s target, the ‘CylinderAnchor’ bone, giving the appearance that the piston is pushed out of the cylinder.
Then the mesh objects, the 5 I want to control by bones, were selected one at a time. Then I shift-selected the armature object, entered pose mode and selected the bone that will control the mesh and did a ctrl-p -> set parent to -> bone. Repeat for each mesh object and now all 5 moving mesh objects are controlled by their bones which is controlled by the bone ‘Flipper’.
Here’s an older video that explains the basics of how I position the bones.
flippermetcyl.blend (683 KB)
Thank you ,
Kinda saved my school project now