Mirror not parametric inside sketch ?

[gamelife4dns]

I made a very simple sketch to show the issue.

There is one user parameter Znum whose value is initially 17.

I draw 2 sketches fully constrained depending on this unique parameter.

Then I change the parameter to any value, say, 8 : compute failure. There is a mirroring that fails.

Thank you.

Steve

[Anonymous]

it's the tangent spline that doesn't work.
the best is to draw it in your sketch 2

[gamelife4dns · Accepted solution]

So I did some changes based on your comment.

I tried mirroring the curves inside the same sketch, the sketch is not locked anymore. I don't know why.

I tried mirroring only the basic curves (lines, arcs) and the points on which the spline is drawn, and then I (re)draw manually the "mirrored" spline. This seems to work, as a workaround.

Any better option ? And why mirrored spline has those sides effects ?

Thanks again.

Steve

[Anonymous]

I don't know but if it works now 😉

[TheCADWhisperer]

It looks like you are creating a gear tooth.

Do not mirror the spline - you don't need the mirror.

Create the half tooth feature and mirror the feature rather than sketch. (Then Circular Pattern the tooth.)

You should only rarely pattern sketch geometry (and mirror is a type of pattern).

I have made fully parametric gears in this way in multiple MCAD softwares for 15+ years.

[gamelife4dns]

Thank you.

I already done what you suggest, here it is https://www.youtube.com/watch?v=kHwaPhKmBt8

Now I'm going further with helical tooth. No way to mirror half tooth in such case as there is no symmetry. Unless you have a tip for me 😉

And then, worm gears, bevel gears, etc.

I want all that fully parametric : pressure angle, module, backlash, teeth number, helix angle, profile shift, center distance... Instant redraw after any change.

Gears are the perfect challenge to learn a parametric CAD software and exploit some advanced features. But I need to know the limits, and I need help for that.

Thanks again.

Steve