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ptc-52803111-Visitor
1-Visitor
June 11, 2014
Question

Using Area Driven Relation to Control Dimension

  • June 11, 2014
  • 2 replies
  • 5088 views

I am wondering if there is a way to control a dimension such that the area of the sketch will be a given value. What I am trying to do is control one sketch based on a height diemsion and the area of a different sketch. I have one sketch that I modify. Then a second sketch that has locked dimensions besides height is meant to be 2 times the area and I currently just modify height until I get it to be what I want it to be. I am trying to automate that process,

Thanks,

Brad


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2 replies

V
vzak12-Amethyst
12-Amethyst
June 11, 2014

There is a way to present sketch perimeter in relation, but imo no way to directly control close loop area.

What you could do is create flat surface from first sketch (hide it if you do not need it), measure surface area of this surface by Analysis feature, do the same for the second sketch.

Add Optimization/Feasibility feature that will put SURF2 as a function of SURF1, and define "variable dimension" the one that can be driven in the dependent sketch.

Surely for simpler shapes you can manage by just relations that use geometrical knowledge, but for complicated sketches with no clear surface area formula you might need optimization.

P
ptc-52803111-VisitorAuthor
1-Visitor
June 12, 2014

I have tried the optimization but I am unsure how to set it up so that it optimizes to the area of the first surface. The optimization seems to only allow for a min and max to be calculated.

Any ideas?

Thanks

V
vzak12-Amethyst
12-Amethyst
June 16, 2014

Sure, here you go :


  1. have 2 surfaces SURF1 & SURF2 each one represents close sketch (given sketch has no area / parameter)
  2. AREA is AF1 (Analysis feature 1) parameter measuring SURF1. Another AREA is AF2 parameter measuring SURF2.
  3. Goal : get AREA (from AF2) = AREA (from AF1) (variable – dimension of SKETCH2).
  4. Add 3rd analysis feature (AF3) of Relation type. Add DIFF parameter there with relation : DIFF = AREA:AF1 - AREA:AF2 (with proper syntax, with your correct IDs)
  5. In FEAS feature (select FEASIBILITY - not Optimization) set goal as DIFF = 0.

You will see - it works like a charm.I would attach a sample part if I knew how to attach here.

Patriot_1776
Patriot_177622-Sapphire II
22-Sapphire II
June 13, 2014

A picture of these areas would work wonders for trying to help....just sayin'.....

I sussessfully used a formula to constantly vary the cross-sectional area of a VSS (with a graph) while it transitioned from a 6" dia circle to an ellipse, and back to a circle of 5" dia.

Perhaps if it's an irregular shape, break it up into smaller shapes that ARE easily solved with a formula and use relations to control it all?

P
ptc-52803111-VisitorAuthor
1-Visitor
June 13, 2014

The slot area is found using the analysis tool. The area of each side of the end turn needs to be equal to 6 times the area of the slot. I want to creo to automatically calculate the height of each end turn in order to be equal to the 6 times the slot area. The slot area calculation is shown below. The End Turn sketch is shown below that.

SLOT+AREA.JPG

END_TURN_AREA.JPG

Let me know if you have any ideas of how to do this.

Thanks

Patriot_1776
Patriot_177622-Sapphire II
22-Sapphire II
June 13, 2014

MUCH better. How accurate does it have to be? By "end turn", you mean removing material?

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