Help! closing open polysurface


#1

Hi there,

I hope someone can help me troubleshoot this problem.

I am trying to close an open ploysurface but I am having a very difficult time. Now, I have extruded a 2d drawing and I am trying to make a “roof” for the open ends. I have tried the blendsrf tool I find that since my curves are complex in certain parts which either makes my it go really wild or the the edges keep pinching. I am trying to make a “rounded roof” rather than flat but not sure which tools to use.

I’ve looked at several video but I’m not sure what I am doing wrong.

Any suggestions?


(Pascal Golay) #2

Hi Athanasia - it really is best to post a Rhino file with the objects you’re asking about.

-Pascal


#3

Thanks Pascal

I’m trying to close the flower of the children’s drawing. I’ve tired tools like rail, Boolean difference and blendsrf. I want a rounded roof rather than a flat point. I thought maybe I could grab points and pull to desired shape but there are no points on polysurfaces. I’ve also tried making this drawing as a mesh the patching the mesh but the same outcome.

My file is too large to send. Brb with a smaller file


(Pascal Golay) #4

Hi Athanasia - select and export just the bits you are asking about to a new Rhino file, and use Save Small in the export…

-Pascal


#5

Wow! Didn’t know you could do that!

Here you goflower head.3dm (7.3 MB)


(Pascal Golay) #6

Hi Athanasia - do you want the top to be flat? Just cap off the vertical walls?

  • Pascal

#7

No, I want the top to be rounded. I’m not sure which tools would be best to do this.


(Pascal Golay) #8

Hi Athanasia - rounded as in ‘puffy’ as if t were a sort of cushion with this outline, or rounded as in all cut out if a more or less spherical surface? (First one hard, second one easy)

In any case the large outer curve has a couple of spots that should probably be tuned up - in the upper left there’s this zig:

(I’d just delete those two points)

And over to the right, you might want to separate the two points that are piled up at the base of the arrow here:

Then you can at least create a solid from that curve and the interior curves, which will be a start.

-Pascal


#9

Thanks Pascal.

Is there something I should know about the “zig”? I’m not sure what’s wrong with it. I guess the second image looks like it is overlapping.

At this point I woulf like this test drawing to be look like a spherical surface. What tool would you suggest? Blend surface?


#10

Pascal,

Here is an image of my blendsrf fail. I’m trying to blend the entire image for the rounded effect. This really shouldn’t be this difficult. What am I doing wrong?
Please help me figure this out.
Example of blendsurface.3dm (7.5 MB)


(Pascal Golay) #11

Yeah… that is not going to work. My guess is that what you want is a sort of ‘bubble’ top to this thing and that s not easy given the curves you have - I’d be inclined to use meshes for this rather than surfaces. It’s possible that using Heightfield may get you something workable, I’ll see if I can make something that is not too terrible.

@Athanasia, I’d say this is possible but very hard to make cleanly to make from surfaces - I’d investigate mesh based programs that can use images for sculpting meshes and use the outline you have, filled in black, as a starting point. Rhino’s Heightfield can make 3d surfaces or meshes from grayscale images but there are better tools I think for the sort of thing you have here - MudBox or ZBrush might be useful.

-Pascal


#12

Here’s what I did - I picked the curve I wanted to put a roof on. This is just ONE of the Eleven curves you had. I cleaned up the curve where you have Cusps, and then created a surface using the Surface - Planar Curve tool. I then drew a curve on the surface using Curve - Freeform - Interpolate on Surface as the “Spine of the Roof”. I then lifted the line an arbitrary distance, turned on Control Points, and brought the ends into contact with the edge of the surface. I then used the new line to split the line that was the outline of the surface. I now have two connected “Rails” so I can build the surface one section at a time using the Surface - Sweep 2 Rails function. To make this work I have to add “Cross Section” curves.
Because your outline is so complex, I put “Cross Section” curves at the sides of the skinny, complex sections of the curve.
Then I started building the roof in sections. Select inside the section you want to surface, and have at it. I’ve attached my version so you can see what I did, and hopefully reconstruct the process.flower head BH.3dm (10.2 MB)


#13

Thanks @pascal and @Brian_Hughes

I decided to do this the most simplest way possible. I’m really trying to learn this program and feel I am missing some basics. Thanks again for your help.


#14

Let me highly recommend various Rhino videos. I learned most of what I use in the video about designing a pair of sunglasses, on Vimeo I think. Great stuff.

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