Parametric UCS?

[SometimesInventorMakesMeAngry]

I created a UCS referencing a User Parameter whose value is an angular dimension. When I change the parameter's value, the UCS doesn't change with it. Is this workflow not possible? Seems like every other part feature in Inventor is parametric except this?

[johnsonshiue · Accepted solution]

Hi! It should work. The part-level UCS has two types (parametric and associative). The former is to click in the Model Space without selecting a vertex. The 6 parameters (3 distance parameters and 3 angular parameters) will be created on the Parameters table.

The latter requires three vertices (first = origin, second = X axis direction, and third = Y axis direction).

Please share the file here. I would like to understand why it does not work.

Many thanks!

[SometimesInventorMakesMeAngry]

Hi, Johnson. See the attached file here. I place a UCS at the Center Point. Then, I create a User Parameter called "angle" with a value of "135 deg". Then I redefine the UCS, click on the UCS's x axis and enter a rotation of "angle". Once I finish redefining, I edit the value of "angle". Nothing happens.

From what you said, it seems like the correct workflow is to try to find the appropriate model parameter for the rotation I need and edit that instead (or assign the value of "d3" to be "angle", I guess).

Part is in Inventor 2019.

[johnsonshiue]

Hi! After you enter the X angular offset or any other offset, you will need to right-click in the graphics windows -> Finish. Otherwise, the change will be reverted as is not committed.

Many thanks!

[SometimesInventorMakesMeAngry]

I understand. I did this. However, upon finish (and the angle being updated to 135 deg), if I now change the value of "angle" to "110 deg" in the Parameters table, the UCS does not update to reflect the new value.

[johnsonshiue]

Hi! I see the issue now. Indeed, the angular offsets cannot be driven by parameters. When you redefine the UCS, the rotation is done in a sequential manner (one axis at a time). When you change one angular offset, the other two may rotate (triad).

This looks like a limitation in the way Inventor UCS works.

Many thanks!

[SometimesInventorMakesMeAngry · Accepted solution]

I managed to find the correct model parameters and entered my angle there (had to subtract it from 180°). It works well now. Thank you!

A tip for anyone that might be reading this in the future is the name of your UCS will be listed in the "Consumed By" column of the parameters table/dialog, which makes it easier to find the right parameters. It also appears that the model parameters are created in the following order:
1. X translation
2. Y translation
3. Z translation
4. X rotation
5. Y rotation
6. Z rotation