Unrollsrf, but with the thickness of the material taking into account


#1

I have a 3D surfacemodel that I should prepare for a laser printer. The model should be lasercuttet in 6 mm acrylic. Therefore, a clean unrollsrf does not work because the model hasn´t got the thickness of paper.

Is there a method where rhino can calculate with the thickness, (where one surface wins over the other in the corners)

The model is huge therefore it is not an option to do it 100 percent manually.

Does anyone have a clever method or know of a plug-in that can be usefull in this case.

Thanks for your help. Best regads Anders


(Willem Derks) #2

Hi Anders,

What we do is unroll the center sheet surface.Yet that is for steel/stainless with no extreme tolerances required.
How is your acrylic being bend and what bending diameters are we talking about?
Bear in mind that bending sharp angles will also expand and compress the material, especially when the acrylic is heated. Ask the people doing the actual shaping, they are most likely to know what tolerances need to be respected and what can be discarded as “good enough”. Or do some small piece tests.

Our experience is that most of the time it is not paying the effort to do a theoretical correct unroll.

An option is to split the surface in parts that are bend either way. Find the spots where the curvature flips and split there. Then unroll those parts and join them for final cutting.

-Willem


#3

Hey Willem! Thanks for your advice! i am not going to work with curved arcryllic. It is actualle just planes. i have attached an example. so it is just about witch surface wins over the other in the corner.

Eksample model to David from Anders.3dm (314.7 KB)

Again thanks


(Willem Derks) #4

Hi Anders,

I see, indeed this is another issue altogether.
In these type of situations I do not know of an automated way to do that in Rhino.

A way you could approach this is like so:

HTH
-Willem


(Pascal Golay) #5

Hi Andy - in case it helps, here is a quick script for this… maybe… see if it does what you need.
To use the script, extract and save the .rvb file from the attached zip archive, then drag and drop the saved rvb over an open Rhino V4 or v5 window. This will load the script, set it up to load on startup in the future and register the alias

PolylinePanelizer

that will run the script much like a regular command. An alias can be typed or added to a toolbar button or keyboard shortcut (F-key).

You select the inner or outer polyline that represents the overall shape, and tell the script which side to offset, and then you are left in the ExtrudeCrv command and you can set the height- that can be scripted as well, but it seems more useful to me to use the Rhino command’s interface here. Currently the base rectangles for the new panels are left in place, but it is easy to make the script delete these as well.

PolylinePanelizer.zip (1.2 KB)

-Pascal