Using a measurement as a parameter

jumpjack_jumpjack

How can I use absolute Y position of a point as a parameter for my model?

For example, I have a point in (0,100,150): how can I extrude a surface by this "100", so as the extrusion lenght changes upon Y position changing?
I can see the "100" in the measurements panels, but how do I link it to my part?

S1mon

https://cad.onshape.com/help/Content/variable.htm#MeasuredD
https://cad.onshape.com/help/Content/measure-ps.htm#Add-variable

rick_randall

S1mon said:

https://cad.onshape.com/help/Content/variable.htm#MeasuredD
https://cad.onshape.com/help/Content/measure-ps.htm#Add-variable

Simon is right. Use variables & configurations, this is kind of a deep dive subject - but you won't regret learning about this (this is where all the magic happens).

Good luck

eric_pesty

Easy to do with a measured variable but how about just extruding "up to point" instead?

jumpjack_jumpjack

Why don't I have the icon for creating a variable in the measures panel?!?




Fortunately I found a "measurement to variable" Feature Script.

S1mon

You need to select two things to get the icon. If you just select a point, it doesn't work (it probably should, but there is a solution). If you select another point or a plane (but not the origin - WTF?) it will work.

jumpjack_jumpjack

yes, but I need the absolute coordinate, not a distance or length; I had to draw lines and planes throught the origin to get the coordinates.

eric_pesty

jumpjack_jumpjack said:

yes, but I need the absolute coordinate, not a distance or length; I had to draw lines and planes throught the origin to get the coordinates.

If you measure from something at the origin (seem like you can't use the origin itself for some reason?), then the x, y, z measurement are the same as the absolute coordinates...

jumpjack_jumpjack

I got it, but I think it's a bug: if I just click on a point and open measurements panel, its coordinates are shown, but they cannot be associated to a variable; but if I click the point and the origin, same values are shown, but they can be associated to a variable.

_anton

jumpjack_jumpjack said:

I got it, but I think it's a bug: if I just click on a point and open measurements panel, its coordinates are shown, but they cannot be associated to a variable; but if I click the point and the origin, same values are shown, but they can be associated to a variable.

Our variable feature doesn't let you measure world-space positions because they tend to not be useful. If you need them, then it's likely that you're not working idiomatically (to which, of course, there are exceptions). Selecting a point and the origin measures the distance between the two, which is allowed.

Can you just make an offset plane from, e.g., the Top plane, and use that as the up-to entity for an extrude?

jumpjack_jumpjack

my model needs a "new origin" : once, after building, connecting and rotating some parts, I determine the position of this new point, I draw a bunch of new parts whose dimensions, orientation and position depend on this new origin.
It's a Foucault siderostat, very difficult to explain in a few words.