topic Re: Can inventor display how a driven dimension was calculated? in Inventor Forum

Can inventor display how a driven dimension was calculated?

benjamin — Sun, 02 Dec 2018 12:01:18 GMT

Hello,
I have a series of sketches which, when taken together, create a fully defined system. I would like to know the equation used to calculate the driven dimensions.
As a simplistic example, if my system were just a right angle triangle and I had set the dimensions of the two shorter sides, could I get inventor to tell me that the hypotenuse is given by sqrt(b^2+c^2)?

My actual system is significantly more complex than this and calculating the equations manually is stretching my trig abilities. I have attached the part file. I would like to know how the the three driven angles are calculated from my 8 set lengths and 3 set angles.

Thanks for any help.

Re: Can inventor display how a driven dimension was calculated?

Mark.Lancaster — Sun, 02 Dec 2018 13:22:34 GMT

@benjamin

First thing.. When sharing files you must indicate what version of Inventor you're using.. In your case its Inventor 2018 (RTM)..

In your sketch if your right mouse click, select DIMENSION DISPLAY and select what you want to see.. UPDATE: I just re-read your requirements.. You want to display how Inventor solved the issue? Is that correct? If so that's not possible. I originally read it as you wanted to display the expressions you created.

Final thing.. Why not just create a single 3D Sketch instead of all these 2D sketches?

Re: Can inventor display how a driven dimension was calculated?

benjamin — Sun, 02 Dec 2018 13:38:42 GMT

Thanks for the response. Yes I would like inventor to display how it calculated the driven dimension, it is unfortunate that it is unable to. I thought that it would be unlikely, inventor probably "cheats" and uses an iterative solver or something for it.

I used multiple 2D sketches just because I thought it may be easier to visualise everything when trying to calculate it by hand.

Re: Can inventor display how a driven dimension was calculated?

johnsonshiue — Sun, 02 Dec 2018 16:09:17 GMT

Hi! Indeed, like Mark mentioned earlier, it is not possible to show how the driven dimension is calculated. It is because, the dimension is a result from the length of a piece of sketch geometry after solve. Essentially, it is like there are so-and-so dimensions and constraints, the flexible line measures as such, which fulfills all the driving dimensions and constraints. In some cases, it is possible there could be multiple solutions. The sketch solver simply presents one that it thinks logical.

Many thanks!

Re: Can inventor display how a driven dimension was calculated?

JDMather — Sun, 02 Dec 2018 17:36:07 GMT

@benjamin wrote:

... it is unfortunate that it is unable to. .

What would you use this information for?

Re: Can inventor display how a driven dimension was calculated?

benjamin — Sun, 02 Dec 2018 23:13:17 GMT

I would like to use it in an Arduino program to control a robotic leg. If I had the full equation for the system I could calculate the servo angles required to move the foot to a location in x, y and z while taking into account other parameters such as the height and current angle of the body.