How to create parametric dimensions?

3dcad

I come from Alibre / Geomagic Design which collects each given dimension into parameter list. Parameter list is accessible when adding new dimensions so it's easy to create parametric designs without even thinking through what parameters/variables are you going to use. I couldn't think of better way to handle parameters.

Is there a way to access given dimensions in OS? How do you create parametric designs?
For example, I wan't to create hole with same diameter to sketch 2 as I made to sketch 1 (and it should follow changes too). Then I wan't dimension from egde to be [dimension from sketch1]+64. Then I wan't pattern with step 32mm as many as fit's to the extrude (follow changes on the size of extrude). Is this currently possible?

brucebartlett

No, but this is what I want too. You can only link ATM with sketcher constraints. 

3dcad

How is this made in solid works? I think Alibre got it right with automatically creating a variable of each given dimension, count or such and you can later rename or create new parameters and equations are supported of course.. Some cads need to first create a variable and then you can use it as dimension - I'm way too busy/lazy to pre-think names and values for variables before modeling..

And if parametric dimensions are still in todo list, I hope the framework is Global Parameters from the beginning.. Meaning that parameters can be accessed from different part studios, assemblies, documents, users, world and the universe!  

brucebartlett

No, but this is what I want too. You can only link ATM with sketcher constraints. 

3dcad

How is this made in solid works? I think Alibre got it right with automatically creating a variable of each given dimension, count or such and you can later rename or create new parameters and equations are supported of course.. Some cads need to first create a variable and then you can use it as dimension - I'm way too busy/lazy to pre-think names and values for variables before modeling..

And if parametric dimensions are still in todo list, I hope the framework is Global Parameters from the beginning.. Meaning that parameters can be accessed from different part studios, assemblies, documents, users, world and the universe!  

james_mcpherson11762

I too would really like to be able to reference previous dimensions while creating a new one. I come from Alibre and really miss being able to dimension a line by saying it's "D1/2" in english: "Half the value of D1" where D1 is an existing dimension in the sketch.

-Jim

jakeramsley

We currently don't have a way to link dimensions with equations yet.  The method that James_McPherson11762 described is what I am most used to as I originally learned CAD via Unigraphics NX.  It seems natural to me that we shouldn't have to define a variable to simply reference a dimension; that is adding redundancy and an extra barrier between the creative process and the implementation.

paul_britton

+1 for the ability to reference existing dimensions, or define dimensions as variables that can be pulled from a table or spreadsheet.

andrew_troup

3dcad said:

How is this made in solid works? I think Alibre got it right with automatically creating a variable of each given dimension, count or such and you can later rename or create new parameters and equations are supported of course....

Belatedly: SW achieves the result you describe. Dimensions are automatically named, "D1@Sketch1" and so forth. A click on a dimension, at the appropriate time, enters that name into a design table or an equation. The dimension name can be upgraded, whenever the user wishes, to something more meaningful.

DanRom624

james_mcpherson11762 said:

I too would really like to be able to reference previous dimensions while creating a new one. I come from Alibre and really miss being able to dimension a line by saying it's "D1/2" in english: "Half the value of D1" where D1 is an existing dimension in the sketch.

-Jim

Are there any updates on this issue? I have the same problem that has been described brilliantly by james_mcpherson11762.
I see that this thread is dated mid-2015. We are almost mid-2017, and given the speed OnShape is developing, I was wondering if meanwhile there is a way for creating parametric dimensions.
If there is none, just a "no" reply will help. At least i will stop searching...
Many thanks

noa

@DanRom624 we do not yet support the ability to directly reference dimensions. The best you can do today is create a variable before the sketch and reference that variable in your dimension. You can then reference that variable again later and it will have a similar effect. To count your vote towards this improvement, please vote on the improvement request here: https://forum.onshape.com/discussion/6315/using-a-derived-dimension-to-set-the-value-of-a-variable