Sketch equal constraint (allow more than 2 selections)

owen_sparks

Hi folks, 

If we have let's say 12 circles in a sketch we want to set the same size then it would be nice to be able to do this with one constraint rather than the current eleven. 

You know because sometimes you just feel the need:-



At first glance it sounds simple, just mimic human behaviour, pick any two, add constraint, then loop, and if it bombs out due to being overdefined then throw error...

I know this flies in the face of constraints always being pairs, but the same could be said of mates and yet we have the group mate, and that works very well.

Cheers,
Owen S.

brian_brady

Step 1: Select all 12 circles
Step 2: Click on the equal constraint
Step 3: There is no step 3

What I want is an equal constraint while drawing the circles. If diameter of a circle is close to an existing circle an "=" shows up next to each, click and both are the same.

owen_sparks

Hi Brian.

Regarding the the steps, are you saying that already exists and I'm an idiot, or that this is your proposal?

Re creation idea. Nice, or how about a drag and snap option?

Imagine we have some circles of various sizes already fully defined. If you click to start a new circle and drag to change the diameter it highlights yellow as you approach each previously used size. That way all to have to do is let go when to get to the one you like. No extra clicks but constrained to size.

Owen S

brian_brady

owen_sparks said:

Hi Brian.

Regarding the the steps, are you saying that already exists and I'm an idiot, or that this is you proposal?

Re creation idea. Nice, or how about a drag and snap option?

Imagine we have some circles of various sizes already fully defined. If you click to start a new circle and drag to change the diameter it highlights yellow as you approach each previously used size. That way all to have to do is let go when to get to the one you like. No extra clicks but constrained to size.

Owen S

@owen_sparks, the workflow I listed already exists. Believe it or not I did it two at a time by activating the constraint tool first for two semesters of teaching modeling using Onshape and a student asked why I didn't do it the other way. He hadn't used other 3D CAD before so he was not locked into his thinking like I was. Students always teach me something as I try to teach them. It's great.

Brian

owen_sparks

Thanks @brian_brady, great info and love the background too.  A day where we can only do the things we were already able to do yesterday is rather dull so thanks for fixing that. 

I'm determined that this equal constraint misunderstanding is not my fault:-
(1) The tools tip must be wrong - Erm, no, it tells you exactly what to do.
(2) The documentation must be confusing, out of date or missing detail. - No again, it's clear, concise, and takes just a few lines of text and a couple of images to make it crystal clear.

So it would appear that I jumped to an invalid conclusion 2 years ago and stuck with it  

Tempted to try to get this post deleted in shame, but if we've both done it then presumably others have too so worth leaving up just for that.

Brings us back to the "OS paperclip" assistant "Oy, CAD monkey, I've noticed to keep clicking on pairs of circles, next time just select them all..."

Cheers,

Owen S.

lougallo

@owen_sparks This is just too good to have deleted... I actually use the al the time for holes.

paul_chastell

Note that behind the scenes we do pretty much what you suggest @owen_sparks in that we add pairs of constraints with one of the entities having all the constraints to it, like a hub with spokes rather than a web. This is typically more efficient and robust when Onshape solves. However, like with adding a constraint to a pair we won't fail if something goes over-constrained, we'll add everything and let you know what isn't happy after.

Also note that we try doing that in other constraints where bulk constraints are unambiguous. For example, 'parallel' works the same way but 'perpendicular' has no idea what you mean by "make these 5 lines all perpendicular". Or if you select a circle and multiple lines then one click on 'tangent' will add tangency between the circle and all the lines. 

owen_sparks

@paul_chastell

Thanks for the insight, it's always interesting to understand a little of how Onshape works under the hood. 

Cheers, Owen S.