I would like to construct some kind of gripper but I have some problems with the axis that blender gives me. Is there a way to self-define the axis that blender uses to rotate the model?
Or can I solve my problem with constraints (which would be better cause then it’s easier to animate ;))?
I attached a .blend file to make the problem clear.
Select a face or an edge and Ctrl-Alt-Space to define a custom orientation. Once you’re done with it, Alt-Space to return to Global, or whatever else you choose.
You only have one object and you can’t use constraints to have them rotate without using an armature. You would have to separate (P, edit mode) the objects, parent (ctrl+P, object mode) to empties and then use constraints.
But there are other ways too. Using procedural duplication (dupliframes) and parenting in this one. gripper_ja12.blend (108 KB)
Interesting mesh so far. (Nice modeling btw.) But for mechanical stuff like this, keep in mind it’s easier to setup for animation if each part is a separate object. Everything that’s together when in edit mode is treated as a single object. It is possible to join and separate separate objects if needed though.
To make it work with a constraint, I ended up deleting all the pieces but one. Then selected an edge ring inside what seemed like the obvious pivot point. Snapped the 3D cursor to that. Exited into object mode and set the origin to the 3D cursor. Moved 3D cursor back to center and set it as the pivot. Duplicated again back to the original number and layout of pieces. (So now they’re all separate objects with respective origins and local axes of that origin positioned and orientated in a useful manner.) Added an empty to use as a target control. Set a transformation constraint on one piece. Setup the min and max and appropriate axes as defined by local space in the transform constraint settings. Tested to make sure it works when empty is moved. Deselected the part with the constraint, selected all the other pieces, then selected the part with constraints in addition. Copied constraints to selected.
If that makes enough sense to follow, you should be good to go.
Thank you all for your answers! I followed pauljs75_ instructions but instead of a “Transform” constraint, I used “Locked Track” (a pretty cool constraint!)
I included my .blend file so you can take a look at the finished setup.
Oooh! I think I can picture how that locked track works without even downloading the .blend. That’s a pretty cool idea. Not just a gripper but you can do various offset rasping motions that way.