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combined projection issue

Genius
Genius
  • "Side_View_(blue)": on ZY plane, both ends are tangent to Z axis
  • "Front_View_(green)": on ZX plane
  • "Combined_(grey)": from "Side_View" and "Front_View"
  • "Top_View_(purple)": projection of "Combined" on XY plane
 
My question:
  • If I need to creat "Top_View" from scratch and use it along with "Side_View" to build "Combined", what rule for creating "Top_Viewneed to be followed to make a smooth "Combined" without sharp corners?

Thanks!

 

ScreenClip [1].png

 

Image.png

 

32 REPLIES

Re: combined projection issue

Siemens Phenom Siemens Phenom
Siemens Phenom

So if I understand correctly you want to create top view as curves.

First you need to define your limits, one of these would be line(3) which is defining the widest point and the tangent at that point, the other would either be a mirror of this line defining the other width extreme point if the height is flexible, or it would be an arc defining the highest point and 90 degrees to line(3) and radius you want that sides minimum to be.

In either case then a bridge curve or spline constrained G1 between the two lines.

 

Steve V

Re: combined projection issue

Genius
Genius

Hi @StevenVickers

 

To create a "Top_View" from scratch and then use it to produce a smooth "Combined" 3D curve, seems not be an easy job. Please refer to the figure below. Thanks!

 

ScreenClip [3].png

Re: combined projection issue

Siemens Phenom Siemens Phenom
Siemens Phenom

Maybe I did not understand what you wanted to do. If you create a top view that is curvature continuous at the touch point with the side view spline (like the rounded square you had previously) then the combined curve will be tangent at that point. If you top view is a circle and only tangent at the touch point to a curve in another plan then mathematically it will have a non tangent point there.

 

Steve V

Re: combined projection issue

Genius
Genius

Hi @StevenVickers

 

I'm sorry for not making the original question very clear.

 


@StevenVickers wrote:

... If you create a top view that is curvature continuous at the touch point with the side view spline (like the rounded square you had previously) then the combined curve will be tangent at that point. ...


I can't understand your statement very well. I think you mean that :

 

  • at the touch point: the circle = G2 continuous
  • at the touch point: the "rounded square" ≥G3 continuous

Then how would you create from scratch the "rounded square" with ≥G3 continuity at the touch point?

 

Thanks!

 

ScreenClip [5].png      ScreenClip [4].png

 

 

 

Re: combined projection issue

Siemens Phenom Siemens Phenom
Siemens Phenom

Thinking about this more I think it is the angle at which the spline comes in relative to the circle.

Think about it you changed the spline for a line and then with an arc. With a line you will get an ellipse, with the arc a parabola (I think) as the tangent angle of the arc or the angle of the line approaches 90 degrees to the circle plane your parabola will get more pointed. Close to 90, theoretically smooth but so sudden a change in direction and curvature that it is effectively a kink.

 

Steve V

Re: combined projection issue

Genius
Genius

Hi @StevenVickers Thanks for your comments! I'm still trying to figure out how to create from scratch the "rounded square".

Re: combined projection issue

Siemens Phenom Siemens Phenom
Siemens Phenom

Need to understand the design constraints better to know how to recommend the best solution.

 

Steve V

Re: combined projection issue

Genius
Genius

Hi @StevenVickers

 

From my previous picture, I know definitely that it's possible to create a "Top View" curve, which along with the "Side View" would give a smooth "Combined" cure.

 

In my design, the "Side View" is ready, now I need to create and adjust the "Top View" to achieve the desired "Combined" curve. I don't choose to use "Front View" since the "Front View" can't capture some key details in my design.

 

In short, I know that a usable "Top View" curve is possible, but I can't create it myself.

 

Thanks!

 

large.png

Re: combined projection issue

Solution Partner Genius Solution Partner Genius
Solution Partner Genius

Hi @surfactant

 

If I understand your question correctly, you want the resultant curve (the combined one) not from your FV & SV, but from your TV & SV.

 

  • If I need to creat "Top_View" from scratch and use it along with "Side_View" to build "Combined", what rule for creating "Top_Viewneed to be followed to make a smooth "Combined" without sharp corners?

Now to answer your question, you need a smooth curve (G1 or G2) in TV right exactly below the end points of the SV. This will give you 'smooth' 'combined' curve.

 

Also, your TV curve needs to be linear (how much you may ask? That's for you to decide) at the projection of end points of SV so that it has enough distance to just bend around the corner.

 

Let me know if this solves your issue.

 

Regards,

Paras Raina
Technical Head | Solid Edge 2019 | NX 12.0.2
MSC Systems Pvt. Ltd. (India)