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unroll developable surface
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January 10, 2013, 06:03:36 AM
I was told in M&M class that this is a feature in Rhino. I am betting TC has it, but I can't find it. It goes something like this: Create several primitive 3D entities, place them so that they intersect, Boolean add them together, explode. I am with them so far, but the last software command, "unroll developable surface" is one I cannot get to in TC ... if it exists. This developable surface is flat and one I can cut on the laser cutter, using colored acetate, and then form build the physical model. Anyone have any idea how I might do this in TC?

Michael

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* January 10, 2013, 10:12:34 AM
#1
Modify>Bending>Unfold Face. Available in Pro only and it works only on Solids, not TC Surface objects.

Henry H

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* January 10, 2013, 02:17:02 PM
#2
'Developable' faces have to be ruled surfaces, no compound curvatures.  For TC, anyway.  Conical, cylindrical, swept lines, or sections of them.  What's 'M&M', Mike?  You have classes to eat candy?!
« Last Edit: January 10, 2013, 02:41:01 PM by murray dickinson »

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January 11, 2013, 07:13:33 PM
#3
HA... I wish it was candy!  Methods and Materials of Construction II. I think this current assignment is leading to a Gehry or Hadid type project. (oh my!) THANkS for answers Henry and Murray!!

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January 17, 2013, 09:22:51 AM
#4
I have attached a quick drawing for definition.

1.) I do not see a way to smooth the faceting. Am I stuck with faceting or did I overlook something? It is an extruded bezier (or other) curve.

2.) lets say the attached drawing is a wall. If I create a similar undulating roof curve above it (horizontal instead of vertical), can I make that roof curve slice the wall that pentrates it?

thanks
Michael

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* January 17, 2013, 10:28:55 AM
#5
"1.) I do not see a way to smooth the faceting. Am I stuck with faceting or did I overlook something? It is an extruded bezier (or other) curve."

Extrude the curve as a Solid, not as a TC Surface (Properties>3D). It'll look better if you disable Degenerative Faceting and use "Quality" Faceter Mode (Options>ACIS). See the attached "Developable1.GIF."

"2.) lets say the attached drawing is a wall. If I create a similar undulating roof curve above it (horizontal instead of vertical), can I make that roof curve slice the wall that pentrates it?"

Yup. Make the "roof" just a tad longer than the wall; Shell it to some small value (e.g., 0.1mm); place it where you want it, being sure it extends beyond the wall at both ends; 3D-Subtract it from the wall, first enabling "Don't remove the subtrahend"; select the wall and Explode it as often as necessary until the Selection Info palette reports it as TWO "ACIS Solids"; select the piece of wall you don't want and press the Delete key. See the attached "Developable2.GIF."

Henry H

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* January 17, 2013, 03:17:40 PM
#6
You can do it by extruding the 'wall' surface a short distance (below the 'roof' surface), shelling it and using 'extrude to face' from the top edge to meet the 'roof' face, too.  As with Henry's description, the receiving roof surface probably has to overlap the wall edge for reliability.  There are 'boolean add' and 'boolean subtract' options that give alternative results, too.   
« Last Edit: January 17, 2013, 03:20:50 PM by murray dickinson »

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January 17, 2013, 07:38:40 PM
#7
thanks Henry and Murray once again. My eyes are crossing right now, but I will get to this in the morning. It is tough keeping up with these damn college kids!  8)

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January 19, 2013, 02:06:18 PM
#8
I am doing something wrong. I think it is shelling. What is shelling?

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* January 19, 2013, 03:24:26 PM
#9
Shell solid is in the modify menu.  It thickens zero thickness surfaces, which you get from open profiles, or hollows-out closed-volume (manifold or watertight) solids.  Shell thickness is limited by face junctions and the area of tightest curvature of a face. 

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* January 19, 2013, 08:39:34 PM
#10
As Murray sez.

Also, when shelling a "solid" object, one has the option to exclude one or more faces from the operation. In the example shown in the attached screenshot, I excluded the top face of the right-hand object.

Henry H

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January 24, 2013, 05:14:05 AM
#11
Thanks fellas. Sorry to impose on you like that, but those were great instructions for using TC in these purposes. I am stubborn I suppose. I want to use TC instead of their preferred software.

thanks
Michael

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January 28, 2013, 07:01:00 AM
#12
What am I doing wrong? I am trying to "unfold face" but each radius is cut up into sections making "unfold face" not useable for my purposes. I extruded this form from the 2D profile. I made sure it was a solid. In other words, I think I need each radius to be one unit instead of cut up or else unfold face will not work as expected.

Michael

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* January 28, 2013, 09:17:36 AM
#13
its extruded the hatch area, Hide the hatch layer, you should then easily see the 'yellow' polylines to extrude producing a smoother curves

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* January 28, 2013, 10:40:12 AM
#14
What am I doing wrong? I am trying to "unfold face" but each radius is cut up into sections making "unfold face" not useable for my purposes. I extruded this form from the 2D profile. I made sure it was a solid. In other words, I think I need each radius to be one unit instead of cut up or else unfold face will not work as expected.

Michael

Your Polyline profile consists of 205 straight line segments. Redraw it, using nine arcs and one line. Extrude that new profile and you'll be able to unfold the object as ten individual flats -- which you can manually assemble into a single flat pattern if you wish.

Henry H

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February 03, 2013, 09:28:29 AM
#15
I almost have it. I can't seem to trim the "roof" back to match the profile of the walls. After I learn how to do that, then I will have to "unroll face" of the 10 walls and 1 roof. I can do the walls now, but I can't isolate the roof for unrolling.  I suppose that means it must remain a solid so exploding will not work.  See attached.

It is probably not important, but when I am done with the above I will draw doors and windows on the unrolled faces, print them at 1 : 96 on Bristol paper, and then build a scale model using the bristol paper.... I know... it is BS, but it is the assignment [part of it... you do not want to know the rest  :-( 

Michael

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February 03, 2013, 02:53:31 PM
#16
I got it.  I just had to walk away, think about it for a bit and I got it to work.  BUT, thanks for all the help!!!

Michael

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* February 03, 2013, 02:54:53 PM
#17
I got it. I just had to walk away, think about it for a bit and I got it to work.  BUT, thanks for all the help!!!

Michael

Yup.

...You're welcome!

Henry H

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