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Old 20th October 2003, 02:55 PM   #1
foxa
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Default Boolean question (I think)

:?: When I try to perform a boolean funtion to make a hole in a printed circuit board by subtracting a cylinder from a rectangle, it works but the rectangle gets subdivided into a bunch of odd sized and shaped triangular surfaces. I have tried to combine these to make one surface and it keeps telling me that they are not adjacent surfaces, what am I doing wrong? While I'm at it - thanks for the great tutorial on POV Ray Woody ( finally READ it instead of just looking at it). :wink:

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Old 20th October 2003, 04:02 PM   #2
-WOODY-
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Default Re: Boolean question (I think)

You're welcome.
From what I understand ( could be wrong ), the reason why it keeps giving you that responce is because either you have some vertices that need to be snapped together and optimized or your edges don't line up exactly. If you take two triangles and line them up exactly with the seem being vertical, and one of the triangles is at a differnt length, it wont combine. The edges ( lines between vertices ) have to be the exact same length and line up to each other. Even if one of the triangles is divided in half, if the total length of the two halfs equal the same exact length of the other triangle, they will combine together.
As far as it making a lot triangles, that's just the nature of the beast. I always try to clean it up first by combining vertices together. The easiest way to do that is to select a good vertice then over to the left in your tools menu, you'll see an x,y,z list box with a "move to" button to the right. Over to the left of the list you'll see a little arrow. Select the good vertice and then hit the arrow to input the coordinance into the box. Now select your fragmented vertice and then hit "move to". Now click-n-drag a selection box over both vertices and hit control+T to snap together.
Do that for all the little fragmented triangles till you get some clean, even surfaces. You can combine a lot easier after that.
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Old 20th October 2003, 05:01 PM   #3
Andy
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Default Re: Boolean question (I think)

Woody is correct about the edges. The Boolean ops sometimes leave T-junctions and might leave vertices which are not shared. Jeff is working on fix for this.

It can leave some very thin triangles so even if it looks like two surfaces are adjacent - there may be another in the middle.

I suggest you select surfaces in pairs (or low numbers) and press c to combine. Remember that you can't have single polygons that contain holes in them so - to have a rectangle with a hole in it, you need at least two polygons.

You may find it better to make this shape another way e.g. revolve a line and flatten the edge vertices. Or, make a cylinder (with no ends) and stretch and flatten one end over the other, then even out the edge vertices. There are a number of ways to accomplish the same shape.

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