topic Re: Motion links inside imported designs in Fusion Support Forum

Motion links inside imported designs

autodeskTH2DB — Tue, 23 Jan 2024 20:34:24 GMT

I have a design with a motor, a gear train placeholder, and a shaft. I don't have an actual gear train, but the placeholder has a rigid joint with the motor. The shaft then has a Revolute joint with the gear train placeholder, so I can spin the shaft. All good...enough.

Now I import that design into another design, in which I connect a horn and other moving components. I find that the Revolute joint in the inserted design does not work. In fact, the Joints folder is grayed out in that linked component.

Are motion links supported across linked designs?

Re: Motion links inside imported designs

jhackney1972 — Tue, 23 Jan 2024 20:48:02 GMT

If you mean by "cross linked assembly" an external assembly inserted into a new assembly, then yes. In the Animated GIF below, as you can see it is an external linked assembly file. The Motion Link controls the linear motion of the screw as it rotates. You can see it works just fine.

If your model has problems, attach it and let the Forum users take a look.

Re: Motion links inside imported designs

autodeskTH2DB — Wed, 24 Jan 2024 18:38:26 GMT

Thanks for showing me it can be done. Unfortunately, it still isn't working for me. I created an animated GIF. It first shows a design with a motor with a shaft with a Revolute joint. Works fine. Note I can drag the joint, as well.

Then I switch to a design that includes that motor. The Animate Joint function works the same, but the Animate Joint Relationships does not and I cannot drag the joint, either. Is there another setting somewhere that enables it?

I don't know if it matters, but the visibility option on the Joints folder is grayed out. I get the message, "Visibility cannot be changed." when I click on it. I couldn't tell if that was the case in your GIF because the background is gray and I can't see the icon at all.

Re: Motion links inside imported designs

jhackney1972 — Wed, 24 Jan 2024 18:46:58 GMT

Could you please attach your model giving you issues?

If you do not know how to attach your Fusion 360 model follow these easy steps. Open the model in Fusion 360, select the File menu, then Export and save as a F3D or F3Z file to your hard drive. Then use the Attachments section, of a forum post, to attach it.

Re: Motion links inside imported designs

autodeskTH2DB — Wed, 24 Jan 2024 23:17:17 GMT

So there are actually four files because there are three linked file in the top level design. I just did a .fdz export. Hopefully, that's all I needed to do.

Re: Motion links inside imported designs

jhackney1972 — Thu, 25 Jan 2024 00:54:03 GMT

The reason the Joint animation will not work in the linked external file is because you accidentally include the RC Motor in RigidGroup 1 in the top level assembly. I will let you use the video to correct your model, I will not return a correct version unless you really need it.

Do not forget to select "Accept Solution" if my post solved your issue, come back if you still have questions.

(view in My Videos)

Re: Motion links inside imported designs

autodeskTH2DB — Thu, 25 Jan 2024 02:34:39 GMT

Thanks for looking at the model. I think I'm on track now.

First, I know the motor was not grounded and I did ground it in my test. I left it ungrounded in the file I posted because the motor is already grounded in the RC Motor file. I think you are saying that the grounded property does not come along when the file is inserted, so I am grounding it in both files.

I guess I should have been more explicit with what I was trying to accomplish.

The motor should be grounded and the shaft should rotate.

The MotorShaftDrive component should be rigid with the shaft and rotate with it.

The MagnetShaftActuator should slide up and down on MotorShaftDrive and rotate with it.

The MagnetCube should be rigid with the MagnetShaftActuator and rotate and slide with it.

The LimitSwitchLever should slide up and down but not rotate. I had this sliding on the shaft, but that actually is not correct and it rotated with the shaft. It should slide relative to the MotorBracket.

All that said, I completely redid the joints in this step by step fashion and got it to work properly.

I see what really happened, now that I've been through this multiple times. You were correct about that Rigid Group. I remember making it by selecting the Rigid Group option and then selecting the RC Motor, but I left the checkbox checked to include all the subcomponents. That included the shaft, so it wasn't going to turn after that. I verified that was the problem by building that joint the same way but unchecking that option and it worked fine.

The insight you gave me is that the joints could be made directly to the components nested inside the inserted design, so I didn't need to involve the top level component at all. I guess both methods work, but that checkbox disappears after making the joint so I prefer the more direct approach.

Bottom line is that it is all working as expected and I have a much better understanding of these motion joints. I also understand, I think, that the grounded property does not follow the link, but I can just reassert it in the main design.

Thanks a bunch!