Simple (?) Constraint Question

larry_hawes

Curious about how to constrain this sketch to preserve the shape through a change in extrusion depth.

http://www.youtube.com/watch?v=YAXIh_deL9o

https://cad.onshape.com/documents?column=modifiedAt&order=desc&resourceType=filter&nodeId=1

michael_mcclain

In the sketch, use a "Parallel" constraint between the top and bottom line to lock those together. Then use a "Perpendicular" constraint between one of your horizontal lines and your vertical line to lock in the 90deg angles there. Finally use "Dimension" and click the angled line and one of your other three lines to set your preferred angle and fully define (All black everything) the whole sketch. This will stop any strange behavior when you modify that extrude.

It's typically best to fully define your sketches to stop them from acting strangely in later changes.
This can be something easy to learn, but difficult to master and just involves you playing around with it and trying different scenarios.
Two tips:

1. Makes sure all sketch entities are black
2. If you are not sure where the sketch has freedom left, click and drag anything blue and you will see what has freedom to move. You can always undo to reset to before this drag movement.

michael_mcclain

In the sketch, use a "Parallel" constraint between the top and bottom line to lock those together. Then use a "Perpendicular" constraint between one of your horizontal lines and your vertical line to lock in the 90deg angles there. Finally use "Dimension" and click the angled line and one of your other three lines to set your preferred angle and fully define (All black everything) the whole sketch. This will stop any strange behavior when you modify that extrude.

It's typically best to fully define your sketches to stop them from acting strangely in later changes.
This can be something easy to learn, but difficult to master and just involves you playing around with it and trying different scenarios.
Two tips:

1. Makes sure all sketch entities are black
2. If you are not sure where the sketch has freedom left, click and drag anything blue and you will see what has freedom to move. You can always undo to reset to before this drag movement.

larry_hawes

Did the trick, thanks so much for taking the time to reply...