topic Re: How can I see parameter/dimension values in real time as models with joints are moved? in Fusion Support Forum

How can I see parameter/dimension values in real time as models with joints are moved?

pferrick — Sat, 11 Jun 2022 17:57:44 GMT

Hi all-

I've been wondering for a while if it is possible for Fusion to export parameter values 'on the fly' so that I can use them to make graphs. I have a model with a number of joints and I'd like to determine mathematically how one part moves in relation to another. A very crude way I've found to do this is to move the model 'by hand' in small increments, pausing to inspect (and jot down) x,y positions of points of interest. Seems as though there must be a slick way to achieve this, but so far I haven't found it!

thanks,
Patrick

Re: How can I see parameter/dimension values in real time as models with joints are moved?

davebYYPCU — Sat, 11 Jun 2022 23:33:57 GMT

More information?

Which Parameter?

Visible joints display displacement values, drive one Joint, the others update the values.

Might help....

Re: How can I see parameter/dimension values in real time as models with joints are moved?

pferrick — Sun, 12 Jun 2022 01:14:53 GMT

I think a picture might be worth a few words here...!

The bottom bar is grounded, and all circles (aside from the middle of the top and bottom bars) are revolute joints. There are motion links such that joints on opposite sides move symmetrically, ie. equal but opposite angles. What you do is push up and down on either of the middle crosspieces, and the top bar moves up and down but at greatly reduced scale. It's basically a (flexure) linear stage.

Since the motion of the top joints is so tiny compared to that of the middle joints, those angles are not useful for figuring out exactly what the positions of the crosspieces and top bar are doing. Of course I can push it a little, inspect the x,y positions of say the center joint and the center hole in the top bar, and graph accordingly. But that's kind of a pain to do over and over. I tried dimensioning the distance between holes, but that doesn't update when I push the crosspieces around. Same if it's a parameter.

If positions (or dimensions or parameters) could be observed in a window somewhere, that would be extremely helpful. Better still would be a button that would enable 'position tracking' of some sort, which I could imagine generating a csv file of the relevant data.

The point of the whole thing is to make a microscope stage with at least micron-scale movements!

Hope that helps clear things up a bit...

tnx,
Patrick

Re: How can I see parameter/dimension values in real time as models with joints are moved?

davebYYPCU — Sun, 12 Jun 2022 02:49:08 GMT

Does this help?

This Sketch is unstable, but with joint limits you can tame the sketch.

Might help....

Re: How can I see parameter/dimension values in real time as models with joints are moved?

pferrick — Sun, 12 Jun 2022 14:26:05 GMT

Thanks...that gets me going in the right direction. I hadn't thought to work right from the sketch, which of course does update dimensions as others change. Not that joint parameters don't, as you first suggested, but on the sketch I can get much more precise position info which is just what I need.

I still think it would be nice if the positions could be 'tracked' to some sort of output as things change, but that might be asking a bit much.

Anyway, thanks again for the help!

Patrick

Re: How can I see parameter/dimension values in real time as models with joints are moved?

davebYYPCU — Sun, 12 Jun 2022 18:24:17 GMT

Given the tracking is now visible, a better man than I could take these numbers and calculate the transitional steps in Excel or similar. ( I had a similar project this weekend, so far happy with Joint values)