Solid Difference Creates Union Instead

Hi GH Gurus,

I am trying to subtract a series of capped Pipes from a Sweep1 Solid. I have done this before on a simpler model and it worked correctly.

The issue I am having is that the Pipes are not subtracting they are adding to the Sweep1 solid.

Images below, code attached. The code requires a point at 0,0,0 to be selected from Rhino.

Attachments:

rotationrampMidSurface.gh, 20 KB

Replies to This Discussion

Permalink Reply by Hyungsoo Kim on January 31, 2017 at 10:20pm

Hi.

I don't have much to say about that function such as sweep & boolean(especially in GH.).

You'll have to go to the McNeel discourse forum and complain about the disadvantages.

In this case, there is a workaround. You can generate more clean and evenly organized closed surface by using "Loft".

Attachments:

rotationrampMidSurface_re.gh, 25 KB

Permalink Reply by Peter Loring on February 3, 2017 at 7:10am

Hyunqsoo,
Thank you for developing a solution. This works, but it runs very slowly on my computer. I don't think it is hitting the processor hard because the fans never kick in, but it takes several seconds to up date any change. But it worked and I got my demonstration piece out in time. Thanks.

Permalink Reply by Peter Loring on February 3, 2017 at 12:46pm

Hyunqsoo,

How did you change the shader and color of the preview to render-yellow? that looks nice, I'd like to use that too.

thanks,

Peter

Permalink Reply by Hyungsoo Kim on February 3, 2017 at 1:04pm

There's the "Document Preview Settings" icon(Circle divided into left and right) on the canvas tool bar. (Upper right corner)

Permalink Reply by Pieter Segeren on February 3, 2017 at 3:52am

Hi Peter - Hyungsoo, that's happening because the (sweep) surface's normals are pointing inwards (the surface is inside-out). To fix that you could reverse the direction of the elliptical section curve before sweeping it. (Or alternatively use negative values for the ellipse's radii).

Permalink Reply by Peter Loring on February 3, 2017 at 7:10am

Hi Peter,
Thanks for the suggestion, I'll give that a try later today. I was thinking it was something like this but didn't know how to solve it.
Thanks,
Peter

Permalink Reply by Peter Loring on February 3, 2017 at 11:29am

Hi Peter,

I added an expression to the ellipse inputs (x*-1) and it solved the issue. The code works lighting fast too. Thanks for taking the time to help me with this.

Peter

Permalink Reply by Pieter Segeren on February 3, 2017 at 4:17pm

You're welcome Peter, and thanks for making the efford to reply.

I really meant for you to reverse the ellipse (using [Flip Curve]), since the negative radii method is a bit too 'alternative', and also notice: it moves the seam to the outside of the sweep... ~:/

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