# Creating surfaces problem

Posts: 64
edited December 1969

I created an irregular shaped flat "table" by making a curve and punching it through a rectangle using the Boolean tool.

But I'm confused because the flat surface has no polygons. It's a single object of sort but I can't really do any vertex editing on the surface (I want to create a "hill" on my "table")

Is there something I need to to have the flat top become subdivided?

Smoothing won't work because I do need to keep the sharp edges.

Thanks.

## Comments

• Posts: 247
edited December 1969

need screenshot

• Posts: 2,232
edited December 1969

What has happened is that the Boolean operation has caused the plane to become an N-gon. Go to utilities ->split into triangles facets that have more than four points. That will make a right ugly mess of triangles - which may work for what you want, or not. If you need a nice clean mesh of quads for what you want to do, you can either spend some time cleaning up the mess, or start again using an alternative method to Boolean to make your hole - there are plenty of those!

Basically, Boolean is a fast and messy method of doing something you could model anyway, so the choice is either save time in the beginning and waste time fixing the mess, or take time to do it right from the start. For some uses, the tri's produced after triangulating the N-gon is quite acceptable, for other uses, not.

• Posts: 64
edited December 1969

Roygee, thank you for your response. I'm a newbie still at Hexagon.

You're right about the jumbled mess of triangles... Eww. What's a better approach?

I drew a curve on the ground plane (z plane) that looks like a thick boomerang. It has about 100 vertices. I'd like a surface mesh of roughly 500 faces. The surface needs additional "topography", so I'll need concentric loops of edges inside so I can create concentric "hills" and "valleys". After that, my plane needs to be bent along a path. This is where my extrude approach broke down. I had the n-gon plane, selected the edge loop and extruded it a few times to get concentric circles, but now I realize, my faces layout needs to be such that I have edges aligned with the bend, because the faces of the inner loops made faces that create jagged edge patterns when bending.

The end result I'm going for is as if you had a large fat boomerang made of rubber foam, and you hold its edges to bend it.

• Posts: 2,232
edited December 1969

Happy to help :)

Before I go misleading you - is this something like you have in mind? It has 360 polys, but with a bit of planning, could be bruoght up to around 500.

• Posts: 64
edited December 1969

Ha!

Yea sure. Looks like you made a circle and squished it?

Anyhow, yea, how did you do this?

• Posts: 2,232
edited December 1969

Yes, that is pretty much what I did :)

Since posting, I've hit on a more elegant solution - I'm preparing a mini-tut on that, but my wife is insisting I go shopping with her, so I'll complete later and post.

Think - draw outline, offset, ruled surface:)

• Posts: 2,232
edited December 1969

OK - back from maxing out the plastic!

I dumped the idea of using offset because it can get messy and difficult to explain how to fix, so went for something not quite as elegant, but effective and simpler for a novice.

It helps to have a reference image, as I have done. Hopefully the attached pics will be in the order of the steps :)

1. Draw the outline using the curve tool - don't close curve. You'll see a concentration of points in some places - this won't do, so draw a straight polyline roughly the guestimated length of the curve. Select the whole curve and go to lines -> line tessellation. Do this a number of times until you get around 33 (for this model - you may need more, depending on how large it is) This will always be an odd number, which is good.

2. With that line selected and in object selection mode, go to utilities ->bend and select the original curve. The second line will curve to match the first. Validate and close curve. This will give you an extra point close to where the ends of the line joined. Select it and hit backspace to dissolve. You may or may not then have an equal number of points - if equal, dissolve another to get it back to an odd number.
Delete the original curve, rotate and scale the new curve to match the outline of the shape. This is where planning and patience pays off in the long run. Move points to match the curve, insert extra points or dissolve as needed. What you are aiming for is have points reasonably evenly spaced, as far as possible with pairs top and bottom opposite and an odd number of points.

3. Copy/paste the curve, scale the copy down and move it to match the outer curve as closely as you can.

• Posts: 2,232
edited December 1969

4. Go to surfaces tab -> ruled surfaces. Click on a point on the outer line - the line will turn red - select a matching point on the inner line - it will form a mesh. Validate, select the mesh in the properties panel and collapse DG by hitting the lightning bolt.

5. Now to close the inside - somehow my screencap got lost! Loop-select the inner edge, deselect one edge at either end in the corner - not important which - and hit bridge. If all went well, this will close the gap.

6. Ring-select the inner vertical edges and hit connect. Select an edge either side of the new centre edge and do the same.

7. Ring-select the outer ring of edges and do the same.

• Posts: 2,232
edited October 2014

8. Now we have too much of a concentration of edges at the outer corners and need to do some poly-reduction. Select three points at each of the two locations shown and weld them - in sets of three, not all together:) Then select the centre edges which caused tri's (highlighted) and hit backspace, "stray only" to dissolve. Do the same at the other end.

9. Give it one level of smoothing. It is essentially done - there is again too much of a concentration of edges at the outer corners for my liking, so I would use the same poly-reduction method to get a more even spread. Weld sets of three close points and dissolve the centre line.

Check for any N-gons by going to selection- >select over-4-points faces. If anything is selected, dissolve the stray points on the outside edge.

You should end up with something like the last pic. You can now do your rounding out, mirror and weld, or give it thickness to get your shape.

Hope I've managed to explain this OK and it is of some use to you - if anything is unclear, just ask:)

Post edited by Roygee on
• Posts: 64
edited December 1969

Roygee, you're awesome!

Thanks a ton for this. It gave me the necessary hints and awareness I needed to accomplish what i wanted. I never considered opening the curve by deslecting an edge and extracting it. Genius!

And the bridge tool was also a good hint, so thank you.

In the end, I use a somewhat different approach, but regardless, thanks to your tutorial, I figured it out, and learned something about Hex.

• Posts: 2,232
edited October 2014

My pleasure :)

I'd love to see what you did and how - always in the market for different techniques.

Just for completeness, here is the more elegant solution using offset and ruled surface - wish I could explain it better!

As well as the final product - my reference pic is very low resolution, so it doesn't look too good. This was UV mapped and textured in Hex - something I don't normally do.

Post edited by Roygee on
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