How to make a custom parametric spiral according to dimensions 2

[Andersen07]

I want to draw a spiral according to the dimensions on the image, but I can't find a way to make it.

Key dimensions:
- The start point should be at 30° with a start radius of 180mm.
- Spiral has 1 revolution (360°)
- (This is the hard one) The maximum height point (where the tangent is horizontal) needs to be at 270 mm from the X axis (notice that this point is not aligned with the Y axis)

I tried law curves and helix, but I can't, for the life of me, find a way to get the "270 mm" maximum height correct.

 

[MANox]

Hey,

It's not math method, but for single case is quick.
Try with this parameters:

The value of 270 dimension is 270.0001.
If You need higer tolerance, try change 287.3525 value.

Best regards
MANok

 

[cowski]

The optimization command can make this an easy task. I drew a spiral like MANox (180 start radius and I guessed with 300 as the end radius), then created a sketch (a single horizontal line tangent to the spiral), finally I created an associative measurement from the center of the spiral to the tangent line. I started the optimization command and told it I wanted the measurement target value to be 270mm and the variable was the end radius of the spiral. It converged to a solution very quickly.

www.nxjournaling.com

 

[Andersen07]

cowski and MANox

Thanks for your answers, but I think I didn't make myself as clear as I should have.

I need these dimensions to be parametric, in the sense I need to be able to control them with some expressions like start_radius, start_angle and final_height

As far as I know, Optimization's target value can't be linked to an expression. Also, the value of final_height is actually linked to another part and should update correctly whenever I change the other part.

Any other suggestions?