I have some trouble solving an issue with combining an IK-Rig with MoSpline.
My task: animating the installation of an insulation collar (for pipes).
In Pic 1 you see the plain model of the collar and the pipe in front view. My first approach was using spline-wrap combined with MoSpline for bending the model evenly curved around the pipe. This works fine but as you can see in Pic 2, there is some distortion going on on the mesh (screw holes). I’ve tried working with restriction/weighting but that doesn’t fix anything. My second approach was an IK-Rig (see Pic 4 - only a quick test) with weighting the screw holes and this works. With a little expresso I attached the IK-Goal to the end point of the MoSpline.
But the very last thing I was not able to solve (wether deep digging the whole net for a solution) is, how to bend the IK-Rig evenly curved following the curvature of the MoSpline (see Pic 4).
Any hints and tipps highly welcome! Or maybe there’s another way doing this (or something similar) with an other technique?
If you split the information, you can have a shape that is following the Spline Warp and compresses it [depending on the bounding box], but also the hard parts on the outside, which will not change the shape. Use the Offset slider of the Spline Wrap
Edit:—- just saw your second tipp ... my comment below is for your first tipp —-
Hi Dr. Sassi,
your tipp does (almost) the trick!
But now there’s another issue. As you can see in the attached pic there is a slight distortion of the meshs’ surface that leads to a missmatch between the collar and the attached screw hole that shouldn’t be there.
The construction (in real) is likely a flat metal plate (approx. 0.3 mm) which is punched in basic shape and the screw holes and other “pins” are bended at 90° +/-Y.
Is there a possibility to deactivate the stretching of the surface ... the bend-deformer f.e. has the checkbox “keep length”.
Great, I had already typed a reply requesting the file (working from images while a scene file could give me so much more information, makes me always want to have the file here!), but I think we are so close that it is not needed anymore.
The part that is exactly in the center-line will be not stretched (or quizzed, for that matter).
So, if the outside needs to be stable (in length), then that center line needs to match the surface of the “metal-strip”.
Since edges can’t be bend, the part on the “metal-strip” defines the segment size of the band. Since this is any way in an “L” shape, I doubt that there will be a lot of shape-change happen.
Sadly none of the approaches leads to the desired result. There is always a detail that doesn’t match (little gaps or offsets or mesh distortion).
My last idea is (also my least favourite): FK-rigging instead of IK. Maybe, instead of animating each joint angle manually, I can develop an expresso which controls the angle of each joint simultanously via user data. I think I’ll give it a try
What is not clear to me, how it is bending around the core. All at once, like one end is fixed and the other end is pulled around and tightened, or is it a progressively bend process like one end is fixed and a hand moves from start to finish to bend a straight metal around?
On the other hand, showing the whole process from start to finish takes a lot of time. If it would be an advertisement and time is critical, I would start bending it, cut, swap out the part, and show only the last bit tighten it while the swapped out part is optimized for the last position.
If you use FK and it an evenly bend, then you can select all joints and create a Selection Object. With that, you have all joints selected in an instant. With that, one entry in the Rotation field will rotate all.
sorry for the late feedback but the last week, several other projects needed attention
However ... I solved the issue with a combination of your approach and one of my several attempts.
I got the best result by combining the MoSpline-Rig with a correction deformer and some Expresso for animating. Here I use the correction deformer to manipulate the points of the screw holes so that the “bended” state matches the original form. This setup does the trick
I didn’t use your cloner setup since it is not rounded enough. But I definitively keep it in mind since we have a collar which has this form (seperate modules you can add or substract to match the pipes diameter).
It was a pleasure to chat with you and once again ... 1000 Thanks for your expert help!!!
Sunny regards from Germany (Ruhrgebiet) ... we finally have Southern Californian Weather :-D