relations in sketchs

franco_otaola

hello,

i have been working for quiet a while in drawings and i keep having the same problem over and over again,
when i work in relations between different points/curves that are not fixed, when i want to make that A adapts to B to have the relation that i want with C sometimes onshape (normal because they are not fixed) do the contrary and adapts C to D to have the relation. for example as in the image some times when i try to put a point parallel to another it moves point 1 and another times point 2 i tried by when choosing the relation doing in the other sens first point 1 and then point 2 or the other way point 2 and then point 1 but it gives the same result, the only way i found to solve this problem is by fixing the point with the fixing tool (but because after some times i need to move it, this trick is a little bit annoying)
here is a image of what i mean, it is a really simple one to show what i trying to explain, i know that in this case it will be solve it by fixing the size of the rectangular part)

the relations are A and C horizontal and A and B vertical, in one case the rectangular draw "adapts" to the point A and in the other one the point A moves to fulfill the relations with B and C. is it possible to chose witch one to do (without using fix before)?

NeilCooke

With no dimensions or fixed constraints, there are multiple solutions, so both results are valid. You should try to keep some dimensional or constraint relationship with the origin, planes, or other model geometry to make it more predictable.

Jake_Rosenfeld

Hi @franco_otaola !

You're fix constraint workflow may not be as restrictive as you think. You can apply the fix, then apply the constraints you care about, then delete the fix constraint by:
1. Clicking "Show constraints"
2. Clicking the fix constraint in question
3. pressing 'delete' or 'backspace' (mac/windows respectively)


I do agree with @NeilCooke though.  Since your sketch should be fully defined by the end of your edits, jumpiness can be solved by adding constraints that define the geometry. 

philip_thomas

My $0.02 - the first entity you pick is the one that doesn't move.
!BOOM

franco_otaola

Jake_Rosenfeld said:

Hi @franco_otaola !

You're fix constraint workflow may not be as restrictive as you think. You can apply the fix, then apply the constraints you care about, then delete the fix constraint by:
1. Clicking "Show constraints"
2. Clicking the fix constraint in question
3. pressing 'delete' or 'backspace' (mac/windows respectively)


I do agree with @NeilCooke though.  Since your sketch should be fully defined by the end of your edits, jumpiness can be solved by adding constraints that define the geometry. 

I have been doing this for the moment (what i tried to describe in the first post ahahah sorry my english is not my main language) but i wanted to know is it would be possible to choose between like  @philip_thomas said for example that the first entity that i pick doenst move (giving one solution and if i pick in the other sens would give the other solution) doesnt work, for example to arrive to the second case of the first image i needed to fix a point and then erase it (as you explain) it was in a big sketch that i had problems. that i was trying to change a distance between two drawings and onshape was rotainting to "obtain" this distance and not moving in one axis (as i wanted)... but i am going to keep doing this technique with the fix option and then erasing it. 

thanks to all