3D model to 2D lasercut for assembly with modelboard / chipboard

Hi there!

I’m rather new to Rhino (quite adept with Maya), and I’m having to revisit a project started by a freelancer last year.

I need to create a reproduction of a 3D model with some lasercut board. We did one iteration and it mostly worked, but had two had some critical design flaws (namely a lack of tabs on the bottom to affix it into holes on the flat ground, and the 2D projection did not account for the tilt of the outside permiter (so pieces had to be manually cut off in order to form the cylinder with the top tilted inwards).

My most critical question is in regards to doing the calculations required to determine the exact 2D cut required to match the 3D model, and the workflow for adding tabs in. It looks like the original artist (who I have been trying to get in touch with) drew a curve with etch and cut properties, placed them inside an instance block, and duplicated it along the Z (vertical) axis, then ran a make2D command on that. I’m not very good at match, but i imagine that the exact angle of the taper towards the roof is directly proportional to the overall length of the 2D cut that goes along the permiter.

Any help at all is greatly appreciated - incl regarding how to attach a picture/screenshot to this? link to imgur for now:

Hello - to attach files including images you can drag and drop or use the upload button


at the top of your message as your typing it.

A Rhino file would help here - with some indication of what you’d like to do - I get it generally but can’t tell where you are now.


oohhhh thanks. i feel silly.

is it okay to attach a .3dm here?

Hello - yes, please attach a 3dm file - in general, if the file is large or complex, Export what you’re asking about to a new file and post that. Any details or directions or clarity you can add by using Dot or object color or layers is welcome.

Keep in mind this is a public forum and anyone can get your file.


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thanks, here it is. it has the model as well as a make2D that we used (missing tabs to anchor it into the ground plane, as well as the perimeter walls not being the correct length to match up with the roof). 20180722-zendo.3dm (1.1 MB)

and here is what it looks like after it was lasercut and assembled (there is a seam of mismatched panels on the back taped together, i would like to mitigate this)

thanks so much for checking it out!

Hello - am I correct that there is basically one set of radial parts (paired in your block) that is repeated about 75 or 80 times in the circle, or is it more complicated than that?


yup thats it. one single piece for the roof (etch lines are so it has some give and can fold to support itself).

two pieces for the perimeter wall (because lasercutter bed is not big enough, they are scored as well because they need to flex to join (this is the one that needs to have length adjusted)). this is also the one i would like to add tabs to bottoms of as ‘feet’ to slip through cutouts in baseplate.

and then baseplate (a circle that matches the diameter of the perimeter walls when they are assembled, with holes for the tabs to fit into).

does this make sense?

Hello - ok, so this , for example,


is to be from one piece of stock that will be scored and folded into shape
from this

and you’d like to add tabs like so:


Do I follow?


thank you for your reply,

if you look at the current Make2D result, you can see that it is actually curves that have been nested inside block instances, so there is no folding between slats (just scoring).

I would like to keep the lasercut the same, but just add tabs to the bottom of the wall slats, and holes to the base plate and have a correct diameter plate (i cant seem to get that to line up).

i will see if i can illustrate this better as well as provide photographs shortly.

Thank you again for your help

Here Pascal, perhaps this will clarify the issues I am having, and what I am trying to do:

So - the wall is in two pieces, the roof one piece, and the flat panels are, for the moment at least, a red herring; you want a total of three surfaces with tabs on the bottom of the two wall pieces, maybe like so:

How am I doing?


amazing!! that looks really good.

yes, the flat panels are just guide geometry. the photo gallery shows the actual physical laser cut and the assembly / integrity issues it had.

the tabs look good! how does one put them in the correct place in the ground surface?

did you add these tabs in 3D in the block instancer?

and did you see what i meant about the wrong length of walls from the photograph? im still trying to figure out how to calculate the length of walls required :confused:

It does look like your wall parts are too long: I made a cone from the base circle and a circle at the top of the tapered walls:

That top edge is 38 and change inches long, and the two flattened walls in your file have an arc there of ~27 inches, that is way more than half the top circle of the cone:


Unrolling that cone and the edge curve (which is how I’d do this, if I understand things) gets me a surface that can be cut in half and DupBorder-ed to get the right part size…

That, again if I understand the thing, can be the basis for the detailing - tabs ands spacing and what-not. Are we on the same page?