topic Re: Assemble > Revolute Direction Change in Fusion Design, Validate & Document Forum

Assemble > Revolute Direction Change

ecnels — Mon, 18 Jan 2016 14:33:06 GMT

Hi Folks:

I have a design using a cutter wheel than rotates against a stationary block in order to cut. The Cutting Edge must rotate counterclockwise, which is the opposite of the way the Revolute Assembly is now working. How is the direction for Revolute reversed?

Thanks!

Re: Assemble > Revolute Direction Change

TrippyLighting — Mon, 18 Jan 2016 16:32:18 GMT

The joint itsef does not have a direction, but perhaps I am misunderstanding what you are trying to achieve.

Re: Assemble > Revolute Direction Change

jeff_strater — Mon, 18 Jan 2016 16:54:22 GMT

@ecnels, perhaps a video of what you are seeing, and what you think is incorrect about it would be helpful.

If you are relating two joints together with Motion Link, there is a "reverse" flag which can be used to reverse the sense of the link:

But, I don't know if that's what you are referring to or not.

Jeff Strater (Fusion development)

Re: Assemble > Revolute Direction Change

ecnels — Mon, 18 Jan 2016 17:15:41 GMT

So, I need to learn more about Assembling, because I set this up as a Revolute Joint and expected that was all that was necessary to rotate. Evidently, there's more to it than that with the other options in the Assemble Menu.

Thanks!

Re: Assemble > Revolute Direction Change

TrippyLighting — Mon, 18 Jan 2016 17:17:51 GMT

Why dont you tell us what you are trying to achieve ?

It is difficult to provide more specific help without more information coming from your side.

Re: Assemble > Revolute Direction Change

ecnels — Mon, 18 Jan 2016 17:33:28 GMT

Here's a screen copy of what I'm trying to achieve. It's a simple counterclockwise revolve of the top cutter disk centerline around the bottom (static) cutter centerline

Thanks Again!

Re: Assemble > Revolute Direction Change

jeff_strater — Mon, 18 Jan 2016 19:00:01 GMT

There is no way in Fusion today to restrict which direction a revolute joint goes. But, the "animate" capability in the command is just a preview for the motion. In reality the joint is free to go any way it wants. If you set up a Motion Study, you can control this direction for that study.

Regarding your screen shot:

The Motion Link command is for relating two joints together. The dialog in your screen shot shows the command in the state where you have only selected one joint:

When you select a second joint you will then see the "reverse" checkbox:

But, this reverse flag only controls how the two joints move in relation to each other, not the direction of each individual joint.

Jeff

Re: Assemble > Revolute Direction Change

ecnels — Mon, 18 Jan 2016 19:42:36 GMT

O.K. so this is the part I don't yet understand: There's only 1 joint, between two different components. There was no Motion Link setup at all for that picture(prior message). The two cutter disks were "jointed" by selecting Assemble > Joint, with a Motion Type of Revolute. The bottom cutter does have a Rigid Joint with the underlying brown base, so it does not revolve during the animation - That's good. The top cutter does spin (as I'm expecting)when animated, but not in the direction desired, i.e. the first thing someone will say to me upon seeing the animation is "But, you've got the cutter spinning the wrong direction! It won't cut! So, is there no way to select a desired Revolute direction? If not, what am I missing about the purpose of Assembly animation?

Of course, we know that many joints & gears in the real-world only work in one direction, so the larger question is how to make sure that's the case in the animations?

Re: Assemble > Revolute Direction Change

ecnels — Mon, 18 Jan 2016 23:38:10 GMT

O.K. so I've resolved this issue. Note the two pictures attached to this reply.

The Issue was: I couldn't get the As-Built Joint command or the Join Command to Assemble parts such that the default direction of revolution could be reversed. Since this is a one-way revolution, i.e. the revolving part must revolve counterclockwise around the center of the stationary part, revolution direction is critical for demonstration and analysis.

The Solution: The As-Built Joint Command requires a Position Selection of the Center of Revolution for the revolving member(s). The member selected for that Center of Revolution Position will affect the direction of revolution either clockwise or counterclockwise. Pay special attention to the small flag attached to the "flag pole" that's anchored to the Center of Revolution. Which ever way that flag's pennant is pointing is the direction the part will revolve.

Thanks for all inputs folks! This is a great forum!

Best Regards,

Re: Assemble > Revolute Direction Change

jeff_strater — Tue, 19 Jan 2016 00:54:34 GMT

Glad to hear it. That's a clever solution, actually. Wish I'd have thought of that...

Jeff

Re: Assemble > Revolute Direction Change

MichaelT_123 — Mon, 23 Apr 2018 05:22:30 GMT

Hi Mr. Ecnels,

... just select the opposite side of the plane you are trying position the joint on.

Regards

MichaelT

Re: Assemble > Revolute Direction Change

mcasselli — Mon, 23 Jul 2018 19:45:52 GMT

I am trying to work along with a tutorial-https://www.udemy.com/fusion360/learn/v4/t/lecture/6893980?start=0 which goes through a workflow for testing out joints before the production of a tv table. I am unable to produce the example so that the joints work, one set is to rotate legs up and down and the other is to rotate a second pair of legs to create a x formation that serves as the support for the tv table. I notice that there are rotational flags in opposition to one another and this seems to make it impossible to move the legs together, though I am having no problem rotating the second pair of legs. I am including two shots of the build so that it is obvious as to the position of the rotational flags. I have tried the as build joint as well as the joint assembly with no luck-Is there really no way to change the direction of the rotation flags and have that affect the overall component?

Re: Assemble > Revolute Direction Change

Anonymous — Mon, 26 Oct 2020 16:35:34 GMT

I am also taking the same Michael Moyer Udemy class on Fusion 360. I have run into exactly the same issue with rotation of the left upper joint being in the opposite direction as the other 3. The rotational direction flag is pointed in the opposite direction of the other 3 revolute joints. When I created that joint, I received a warning notice "Selected joint will result in conflict". Like you, I could not animate the model. As a test case, I was able to build a 4-bar linkage, ground one of the links, and animate the remaining 3 links. I understand the principle, but cannot apply it to this specific case.

I know you posted this issue over 2 years ago. Did you ever find a solution? I am in the early stages of learning Fusion 360 after 15 years of using TurboCAD (similar to AutoCAD). TurboCAD individual layers ("bodies" in Fusion) can have their own local coordinate system that is different from the global coordinate system. I wonder if this might be related to the problem, but I have not seen anything in Fusion 360 about local coordinate systems.

Thanks for any assistance you can provide.

Re: Assemble > Revolute Direction Change

TrippyLighting — Mon, 26 Oct 2020 16:42:39 GMT

It would probably be helpful if you could share the model and create a screencast demonstrating the issue.

Re: Assemble > Revolute Direction Change

Anonymous — Mon, 26 Oct 2020 18:23:51 GMT

My problem is the same as the one initiated in Message 12 of this string by mcasselli. See my attached screen clips, which are the same as the issue raised by that poster. See the error message screenshot first, then the screenshot showing the different direction of the rotation flag.

Thanks.

Re: Assemble > Revolute Direction Change

Anonymous — Mon, 26 Oct 2020 19:14:35 GMT

I believe I have found the problem. I found that suppressing the slider
joint between the dowel and the center slotted support allowed the revolute
joints to rotate as intended. I wanted to reply with a solution in the
event others run into the same problem.

Thank you for your time.