Flowing Tutorial and tangent constraint issue

allen_stewart

Hello All,

I am new to Onshape and Im following the text tutorial and I am having a little problem with the tangent constraint feature.

I have the large circle connect to the small circle using two lines.  As soon as I add the tangent constraints (like the tutorial shows) both circles become the same size.  Im guessing im doing something wrong but Im following the tutorial exactly step by step.

https://cad.onshape.com/help/#tutorial-sketch.htm%3FTocPath%3DTutorial%7C_____2

Thank you

3dcad

Try dimensioning circles first, resize might be because of Onshape trying to scale things for you..

Onshape has a functions that allows you to draw a sketch with 'free hand' and when you add the first dimension, it will scale the rest of the sketch accordingly. This is sometimes very helpful, some times a bit annoying - but the important thing is to know it will do this everytime.

rbaek

allen_stewart said:

Hello All,

I am new to Onshape and Im following the text tutorial and I am having a little problem with the tangent constraint feature.

I have the large circle connect to the small circle using two lines.  As soon as I add the tangent constraints (like the tutorial shows) both circles become the same size.  Im guessing im doing something wrong but Im following the tutorial exactly step by step.

https://cad.onshape.com/help/#tutorial-sketch.htm%3FTocPath%3DTutorial%7C_____2

Thank you

Are either of the circles dimensioned/constrained already? I'm guessing what's happening is that since you haven't dimensioned or constrained either, applying the tangent constraint is trying to resize the circles to make the sketch solvable. Are there any other sketch entities in the same sketch, or are you only working with two circles?

allen_stewart

Only working with the two circles and lines.  I was following the tutorial line by line and ran into this problem.  I will give your suggestion a try.  Thank you

3dcad

Try dimensioning circles first, resize might be because of Onshape trying to scale things for you..

Onshape has a functions that allows you to draw a sketch with 'free hand' and when you add the first dimension, it will scale the rest of the sketch accordingly. This is sometimes very helpful, some times a bit annoying - but the important thing is to know it will do this everytime.

allen_stewart

thanks guys

andrew_troup

My first thought is that the lines might be constrained without you knowing it: perhaps both are horizontal, or they are parallel to each other. 
In either case, establishing tangency with two circles would then force those circles to be the same diameter.

To find out if they're constrained, edit the sketch, and tick the box for "show constraints"

matthew_mucker

I ran into the same problem. It's not a good sign when the beginner's tutorial doesn't work when followed step-by-step.

Going through the tutorial a third time and dimensioning the circles first appears to work.

Looks to me like the tutorial needs to be updated.

johan_blohm

This is a very old thread but I'm running into the same problem when following the tutorial "5. Sketch Tools: Intermediate Sketching. I have tried to go back from scratch several times following the tutorial to the letter but the instructions doesn't add upp leaving you with an incomplete drawing. VERY frustrating!