topic Re: Need help rigging with constraints- mechanical animation in 3ds Max Animation and Rigging Forum

Need help rigging with constraints- mechanical animation

Anonymous — Mon, 06 Apr 2020 18:40:10 GMT

Hi All, I attached a gif.

I animated this the old school way, just keyframing in the open position then closing and setting more keyframes.

I'd like to set up a rig where I can push and pull the blue piece and have the 2 outer pieces open and close.

The real issue I've having is keeping those arms around the "pins" as you can see. The geometry is intersecting.

I've tried unsuccessfully with constraints. Any help would be appreciated. Would you use bones? Just constraints? etc?....

Re: Need help rigging with constraints- mechanical animation

leeminardi — Tue, 07 Apr 2020 14:25:57 GMT

Can you post the Max file?

Re: Need help rigging with constraints- mechanical animation

leeminardi — Tue, 07 Apr 2020 14:44:55 GMT

The mechanism has 4 components, 1, 2, 3, and 4. The pivot for 3 should be at A.

Place a point helper at B linked to 1.

Position 3 so that its pivot is at the location of 2 where is pivots.

Link 3 to 2.

Place a LookAt constraint on 3 to look at the point at B

Link 4 to 3 and uncheck its Inherit Rotate Z Link Info (hierarchy tab, I am assuming a top view).

Make sure all pivots have the same z world coordinate (again, assuming top view).

The attached file is a crude representation of the system.

Re: Need help rigging with constraints- mechanical animation

Anonymous — Tue, 07 Apr 2020 16:59:02 GMT

@leeminardi THANK YOU! I downloaded your file and that is basically it.

Yes, I can upload my file. The pieces were imported from Solidworks.

You'll see in my file that there are 3 sets of those arms. Would I just rig one, then copy/instance them?

Re: Need help rigging with constraints- mechanical animation

leeminardi — Tue, 07 Apr 2020 17:58:00 GMT

"You'll see in my file that there are 3 sets of those arms. Would I just rig one, then copy/instance them?"

No. Get one arm to work correctly then you can create a wire parameter between it and the other two arms. Wire the rotation of the rigged arm to the rotation of the other arm.

I noticed that you have some objects grouped. I do not think you want to use groups.. Lining object is better.

Let me know if you have additional questions.

Re: Need help rigging with constraints- mechanical animation

Anonymous — Tue, 07 Apr 2020 18:27:01 GMT

@leeminardi Ok, sounds good. I might need some help once I get to that part because I've never used wire parameters.

Re: Need help rigging with constraints- mechanical animation

leeminardi — Tue, 07 Apr 2020 18:53:38 GMT

OK.

I found your file difficult to work with because of the grouping and the unclear object naming convention. It would be helpful to have arm1, arm2, arm3, etc.

Re: Need help rigging with constraints- mechanical animation

Anonymous — Tue, 07 Apr 2020 18:55:16 GMT

@leeminardi I'm ungrouping and renaming everything right now so it's simpler to work with.

Re: Need help rigging with constraints- mechanical animation

Anonymous — Tue, 07 Apr 2020 19:10:51 GMT

@leeminardi I uploaded the new file. I removed my old animation and renamed and color coded everything. The outer walls need to be in 2 pieces for an animation I will do later. I attached/detached objects as needed so there are no groups. Thank you!

Re: Need help rigging with constraints- mechanical animation

Anonymous — Tue, 07 Apr 2020 20:06:15 GMT

@leeminardi I think I got it to work. I uploaded another file with one link working. Could you walk me through the wire parameters? Especially how to make it work on the other side. Thanks so much.

Re: Need help rigging with constraints- mechanical animation

leeminardi — Wed, 08 Apr 2020 01:18:10 GMT

I couldn't get the WIre Parameter or a Transform script to work. Perhaps that is because of the LookAt constraint.

An easy solution is to add 2 point helpers and link them to LeftWallBase. Make sure they have the same z coordinate as the Links. Then add a LookAt constraint to link2 & 3 to look at the two points respectively as shown below.

Re: Need help rigging with constraints- mechanical animation

Anonymous — Wed, 08 Apr 2020 03:10:00 GMT

I actually just used the same technique for the other links, using the same lookAt constraint you first described. It works great. Thanks again for your help