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Boolean Puzzler
Posted: 14 July 2012 06:35 PM   [ Ignore ]
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Okay, well, for me it’s a puzzler…


I never use booleans, I hate them, they always cause trouble. Like now. But in this case there just isn’t any other way. Maybe someone can help me figure out how to do this simple boolean…


I have two objects, a 10x10 mesh plane, and a kinda triangular-ish cube.


What I want to do is have the sides of the cube slice the mesh where they intersect, leaving only the plane mesh that’s inside the cube cut in the shape of the triangular-ish cube. The closest I’ve come is being able to get a single polygon in the shape of the cube, but the detail of the poly mesh (all of the 10x10 polygons) disappear.


And it took me the longest time to remember that when they say in the manual to select an object, then the tool, then the other object, they mean you MUST SELECT THEM IN THE 3D VIEW, not in the instances list (or whatever its’ called). ARRGGGHHH !!!!!


Anyway, thanks for any help…..

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Posted: 14 July 2012 07:30 PM   [ Ignore ]   [ # 1 ]
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Once you choose boolean then use the icons to cycle thru the cut types.Use surface2 cut by Volume1 to get the desired effect

BTW. How did you make the plane? did you use the Grid option or other. This will make a difference with the outcome.

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Posted: 14 July 2012 07:44 PM   [ Ignore ]   [ # 2 ]
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If I understand you correctly you want to cut a shape into a 10X10 mesh and preserve the grid of the mesh.

One non-boolean way of doing this is to use tesselation by slice (third choice down under tesselation) and then use the middle option to “draw” the shape.

I wasn’t real careful where I placed my template, so forgive my inaccuracies. smile

All in Front View

I made a line drawing of the template, then filled it with coons surface tool.

Then I made the 10 X 10 grid.  I added a shading domain to the template so I could see it better as it is on the same axis as the grid.

See bottom image.

The top image is a result of deleting the new polygons of the shape drawn by tesselation.

Lastly, I deleted the stray tesselaton lines using backspace and chose “remove stray.”

A bit more work and I hope this is what you were asking.

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Posted: 15 July 2012 12:48 AM   [ Ignore ]   [ # 3 ]
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Tugpsx - 14 July 2012 07:30 PM

Once you choose boolean then use the icons to cycle thru the cut types.Use surface2 cut by Volume1 to get the desired effect

BTW. How did you make the plane? did you use the Grid option or other. This will make a difference with the outcome.


Yeah, I cycled thru and tried every last one of them, even varied which object I selected first, nothing gave me even close to what I wanted. Like I say, the problem was that it erased the individual polygons in the 10x10 mesh, and the result was always just a big, single polygon.


FWIW, I used Grid to make the mesh. Does it matter?

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Posted: 15 July 2012 12:56 AM   [ Ignore ]   [ # 4 ]
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Design Acrobat - 14 July 2012 07:44 PM

One non-boolean way of doing this is to use tesselation by slice (third choice down under tesselation) and then use the middle option to “draw” the shape.

DOH !!! (and I’m smacking my forehead with my palm…)

For the life of me I couldn’t remember how to do what other booleans do, which is stamp the pattern of the cube on the mesh, and then erase all the polys around the edges. But tesselation by slice is a nice way to do it. Thanks.


My only remaining problem is that the actual mesh I’m doing it on is thousands of polys, and cleaning up the edge polys might be a big chore. But at least it’s do-able in the amount of time it would take me to figure out the boolean approach.


Cool. Thanks.

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Posted: 15 July 2012 02:41 AM   [ Ignore ]   [ # 5 ]
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Another very simple way to achieve this is to use the surface tessellation tool to cut the shape in the grid, delete the facets inside the shape and extrude the edges of the shape and bridge - you will end up with some tri’s , but those are easily dealt with.

What method you use will depend on what feeling and emotion you want to convey - just kidding grin

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Posted: 15 July 2012 03:16 AM   [ Ignore ]   [ # 6 ]
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Thanks all….


I’m still gabberflasted that there isn’t a quick and easy boolean way to do it. I’m sure there’s got to be a way to at least use the cube to slice a shape into the mesh. And there has to be a way to use the cube as a cutter to chop the mesh and discard the rest. Hmmm…very strange.

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Posted: 15 July 2012 04:43 AM   [ Ignore ]   [ # 7 ]
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It’s not that it can’t be done - it can.  Just that Hex is not that good at this particular task, without some help from the user.  Carrara also takes away the grid edges, but at least triangulates the rest, so you have something left to work with.  Blender is far better at this, but is limited in the variety of Boolean operations it offers.  Maybe the expensive jobs do it better.  I think that the problem is that technology hasn’t evolved to the point it can appreciate aesthetics, so we work within the limitations.

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Posted: 15 July 2012 07:08 AM   [ Ignore ]   [ # 8 ]
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Joe

Sometimes it is useful to have a clean start for further good modelling.

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Posted: 15 July 2012 07:47 AM   [ Ignore ]   [ # 9 ]
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@ JoeMamma2000
What are you trying to model It could make a difference.
As long as your mesh is clean and you do not have artifacts when rendering, just do what you have to do to achieve the final result.
  If it is for an animation or game make sure it deforms correctly, if it is for a still image then anything goes as long the end result looks the way you intend it to.
Do not over think it if you don’t have to.

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My Video Tutorials on Youtube
http://www.youtube.com/user/johnnybevo?feature=mhee

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Posted: 15 July 2012 07:58 AM   [ Ignore ]   [ # 10 ]
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I agree what I did there could have been achieved much more simply, it really does depend on what you are doing and what is required for the end result.

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Posted: 15 July 2012 02:16 PM   [ Ignore ]   [ # 11 ]
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johnnybevo - 15 July 2012 07:47 AM

What are you trying to model It could make a difference.

Whenever I see the name “johnnybevo” I think of the very old (1950’s??) song “Johnny Angel”, and I start humming it. That song was way before my time, though. Not sure how I know about it…..


Anyway, my ultimate goal is to make a kinda diamond shaped necktie, that is comprised of a very uniform, fairly dense mesh of quads for use in the Carrara cloth simulator.


And I think the winner in the “How to Make a Diamond Shaped Necktie for use in the Carrara Cloth Simulator” is Mr (or is it Ms) Tapioca Tundra (sorry if I got the name wrong, I can’t see previous posts when I’m making a new post). Runner up is Mr. Acrobat, for another elegant and insightful approach.


Anyway, in line with my continuing belief that booleans are of the devil, and there’s always a better way, Mr. Tundra has hit upon a brillant solution, for which I am indebted. Thank you.


How I do’ed it:


I take a simple cube. Rotate it 45 degrees so it looks kinda like a diamond. Delete all but the front face, then select the top vertex of the diamond and stretch it up so you have a necktie.


Then, as Mr. Tundra so brilliantly suggests, merely tesselate until my heart is content, and I get a nice mesh. Not perfect, since the top polys are bigger than the lower polys due to the stretching of the original shape, but good enough for my needs. Pretty cools. Thanks.

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Posted: 15 July 2012 10:29 PM   [ Ignore ]   [ # 12 ]
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Ahh - so you want a high-poly neck tie with diamond tessellations?

1.  Grid
2.  Taper
3.  Add a couple of extra horizontal edges across the bottom and pull down verts to form pointed end
4.  Do one diamond tessellation

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Posted: 16 July 2012 12:27 AM   [ Ignore ]   [ # 13 ]
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Hexagon tie with some Carrara physics.  heh

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