Help intersecting solids accurately

Hi there.

I’m 3d printing some boxes and I want to show in the print some dado joinery. How would I do this with accuracy in rhino?

Here’s my file:
intersecting question.3dm (465.8 KB)

this is a sample of my fail.

Hello- the Intersect command may be what you are looking for…


I tried that command prior but not everything intersects.

Hello - I guess I am not sure what you are looking for - do you want to know how they intersect now, or do you want them to intersect in some special way, if so can you describe that? Even all around for instance?


I want the dado joinery to match perfectly. It doesn’t seem to work when I intersect the to panels together. I am now starting from scratch again. What’s the best way to complete joinery with the least amount of commands?

I try boolean difference but it doesn’t work well.
Seems simple but very time consuming.

What’s the simplest way to design joinery in rhino?
dado joinery.3dm (44.7 KB)

I also found this but I’m not sure about running script on rhino

@Athanasia How much experience do you have with Rhino? Have you created other geometry or is this your first project?

Do you have experience with other CAD software?

Yes I do, but I don’t use it continuously, on and off over the years.

I’ll take you set-by-step on my attempts

1- made a solid box
2- drew out the dado using polyline command

option 1:
use that dado line =, try to extrude then boolean difference. doesn’t work.

option 2: draw out the entire outline outline of the box and join the poly lines together. doesn’t work. It only joins the edge but and not the entire line.

Screen Shot 2022-04-22 at 6.39.53 AM

I’m not sure why I can’t simply draw the line and subtract it from the other. What am I doing wrong?

Other times it doesn’t allow me to even join when highlighted.

It’s really frustrating.


I guess the only way to do this is draw out the poly line to a complete closed line then cap the open faces.

@pascal @davidcockey

Now, I am trying to simply cut out a groove. The box panel created above and a box with the exact size that I need for the groove insert. I try and boolean difference but constantly getting the wrong edits. What’s the best method?

looks like I need to overlap the groove (box) with the large panel (box) then boolean difference. It’s what I want but now my measurements are incorrect. What’s the proper way of doing this?
Screen Shot 2022-04-22 at 8.16.55 AM

When I attempt to difference with the correct measurements this there is a small gap like this…

Hi @Athanasia
It’s impossible to tell from just a screen dump - post your file. If you are still basing things of the file you posted earlier, you have a segment that’s shorter than the others. Check your dimensions and use osnaps to make sure you are placing things precisely. I’m still not sure exactly what your problem is? Is it making the cut-outs, getting the spacing right, optimizing the work flow or something else completely?
HTH, Jakob

1 Like

thanks @Normand

I’m definitely using the osnap, usually “end” or “point”.

My initial problem was that wasn’t able to intersect the two box panels accurately in the dado grooves created (for some reason it failed, maybe I am missing something.) I tried intersect but it didn’t work.

I then started a new box from scratch, because the joints didn’t line up correctly ( it would leave a small gap between each groove and I need the joint to be pocket tight). I thought I could create a sold rectangular box then create a polyline (extruded the line) that would allow me to subtract the dado joints from the rectangle box. This didn’t work either.
My next thought was that I need to create a closed polyline with the dado grooves, then extrude the curve into a solid. This worked, but when I tried to boolean subtract another rectangular box, to create another groove on the top surface to create a ledge, i am constantly getting gaps.

I’m missing something in my steps or workflow and not sure what i am doing wrong. It shouldn’t be this time consuming.

It is very difficult to impossible to resolve your difficulties without a .3dm file with the geometry. You can upload a file by clicking on the vertical arrow icon above where you type a post.

For the last few hours I made the first side of the box. I will now make the second side that needs to fit perfect with this first side. What would you suggest would be the easiest way of doing this?

my thinking-

a) Either, I trace out the negative space of the grooves with a poly line command with osnap on to form a closed line then extrude into a solid.

b) reflect command? this won’t work cause it’s not a subD

I’m obviously missing some important information of what i can
sample correct box side 1 .3dm (324.4 KB)

ok, here is the other side.
other panel.3dm (596.7 KB