New to parametrics: how do I make a basic cube controlled by one dimensional value?

russ_taber

Made a centerpoint rectangle. set a side dimension to 50mm. added an equal constraint to a perpendicular side. 
Now I want it to extrude to the set 50mm dimension. If I change the dimension, the cube will scale equally.

I must be overthinking it. Best practices? 

traveler_hauptman

Best practice would be to use equations to establish the relationship. Equations functionality is not released yet. Until then, you have to use a hack.

While I wouldn't typically use a hack for production work, it can help you get more familiar with how things (currently) work. Points for the most creative one....

traveler_hauptman

The non-creative version: https://cad.onshape.com/documents/2149057fbe6c410e9a3e4746/w/bb0d56bee3f14f61ae5d0173/e/d258de12d5194b3e95fff205

traveler_hauptman

When you project from one plane to a perpendicular one, all the projections end up in a line... but that's ok because we only need the one line.

Coincident mates on the shared edge work fine as well.

jakeramsley

I would use a sweep with the system as is.

1. Sketch a center-point rectangle and make the lengths equal to be a square.  Dimension the square, this will be the dimension to drive the cube size.


2. On an orthogonal plane, sketch a line from the center of the rectangle that is perpendicular to the rectangular face.  Select this line and choose it to be equal that of the rectangular line.


3. Sweep the square face along the perpendicular line.  This should create a cube.


From here you can go back to sketch 1 and edit the dimension.  The cube should update accordingly.

traveler_hauptman

Best practice would be to use equations to establish the relationship. Equations functionality is not released yet. Until then, you have to use a hack.

While I wouldn't typically use a hack for production work, it can help you get more familiar with how things (currently) work. Points for the most creative one....

russ_taber

Cool. Glad to hear it. Did try using the new copy and paste sketch command add a constraint but to no avail. Equations make much more sense.

traveler_hauptman

The non-creative version: https://cad.onshape.com/documents/2149057fbe6c410e9a3e4746/w/bb0d56bee3f14f61ae5d0173/e/d258de12d5194b3e95fff205

russ_taber

traveler_hauptman said:

The non-creative version: https://cad.onshape.com/documents/2149057fbe6c410e9a3e4746/w/bb0d56bee3f14f61ae5d0173/e/d258de12d5194b3e95fff205

Neat. That works. How did you link the constraints?

traveler_hauptman

The horizontal line from the origin in the first sketch is projected ('use' tool) to the second sketch.

russ_taber

Sorry, not following how your project (Use) perpendicular sketches. Can your rotate sketches?

traveler_hauptman

When you project from one plane to a perpendicular one, all the projections end up in a line... but that's ok because we only need the one line.

Coincident mates on the shared edge work fine as well.

russ_taber

That makes more sense. Thank you.

jakeramsley

I would use a sweep with the system as is.

1. Sketch a center-point rectangle and make the lengths equal to be a square.  Dimension the square, this will be the dimension to drive the cube size.


2. On an orthogonal plane, sketch a line from the center of the rectangle that is perpendicular to the rectangular face.  Select this line and choose it to be equal that of the rectangular line.


3. Sweep the square face along the perpendicular line.  This should create a cube.


From here you can go back to sketch 1 and edit the dimension.  The cube should update accordingly.

russ_taber

Thanks Jake. Very nice. Starting to get the hang of things. Really liking the power of parametrics.

andrew_troup

Nice solution, @jakeramsley  !

traveler_hauptman

@jakeramsley Nice!

nav

Great solution @jakeramsley