How Do I ? Make a vertical width the same as the horizontal height

scott_l_holmes

https://cad.onshape.com/documents/5fd587281ae10ca5381fb830/w/e545b0c197956d7f58969f38/e/1005151602729b69a8f62a5f

Total noob here. In the above drawing is a sketch in the Part Studio 1. I would like to add a constraint that the height of the top is equal to width of a side. Not sure what I need to do. The idea is that all three pieces (that I've sketched so far) are the same width/height .1 meter. I'm not sure about the .1 meter and I would like to change it later (.125 meters let's say) and have all three pieces change.

coleman

Use the "equal" constraint in your sketch.  


I didn't look at your doc...but from what you are describing the equal constraint should constrain everything the way you want. 

3D

Another way you can do this is set a variable (using the "X" function). You can set: x = 1m or whatever you want then when you set the dimension in the sketch, instead of putting the measurement, you can prefix the x with #. So select the dimension feature, select your points as appropriate type "#x" (without the inverted commas in the input box for each of the dimensions you want to be the same measurement. When you want to change all the set dimensions, you change all by altering the value in "X" on the feature list.

 See attached: Note the value you are referencing always must precede your sketch.

shanshan

scott_l_holmes , I  think maybe you want to make the height of the top rectangle  and the width of the left and right rectangles equal , but do you notice that you have given dimensions 0.05 for them ?if you add "equal" to them again , they will be over constrained , that's why the sketch turns red.

coleman

Use the "equal" constraint in your sketch.  


I didn't look at your doc...but from what you are describing the equal constraint should constrain everything the way you want. 

scott_l_holmes

Thanks for the response. I tried to make the edges "equal". I selected the vertical edge of the "top" shelf. Then I selected the horizontal edge of the "side" and selected the "equal" constraint but everything goes red. Is there a way to dig into the constraint to see why that's not working?

3dcad

Something else is defining geometry. Click show constraints and try to remove coincident constraints (probably automatically created) around geometries you wan't to make equal.

Constraints are tricky but powerful, take your time and remove one by one - use undo if you remove the wrong one..

ps. First make sure you don't have dimension in both equal geometries..

pps. didn't look the doc either, I don't want it to be first in my recents list in the morning at work..

mahir

I looked at your doc. I'm not sure if you're talking about controlling the length of each rectangle, or the width. Either one is doable. If you want to control the length, just add an equal constraint. When I did it, there were no issues with the sketch going red. If you'd like to control the width, you can do the same thing, but you'll need to remove one of the .1m dimensions to avoid being over constrained.

https://cad.onshape.com/documents/5820f154dda54d1037280092/w/37d8c8d74d2a9e1565e3480c/e/fd1ad9c0bf83bf9c32dae0df

3D

Another way you can do this is set a variable (using the "X" function). You can set: x = 1m or whatever you want then when you set the dimension in the sketch, instead of putting the measurement, you can prefix the x with #. So select the dimension feature, select your points as appropriate type "#x" (without the inverted commas in the input box for each of the dimensions you want to be the same measurement. When you want to change all the set dimensions, you change all by altering the value in "X" on the feature list.

 See attached: Note the value you are referencing always must precede your sketch.

shanshan

scott_l_holmes , I  think maybe you want to make the height of the top rectangle  and the width of the left and right rectangles equal , but do you notice that you have given dimensions 0.05 for them ?if you add "equal" to them again , they will be over constrained , that's why the sketch turns red.

scott_l_holmes

Many thanks to all who assisted. I think I understand everything much better now. @shanshan zeroed in to the main thing that was tripping me up with the "equal" constraint. I did not realize I had two dimensions for the thickness. Deleted one and I was able to get the "equal" constraint to do what I wanted. I was also able to use the tip @3D left to specify the overall thickness of the wood. I also used an expression in the dimension I used to specify the position of the top shelf to make it half the thickness of the wood. Golly. I can't believe how powerful OnShape is and how helpful this forum is. Thanks!