Joining To Solid Problem

I am attempting to make a solid from the revised surfaces I changed for the customer.

  1. Certain surfaces do not want to cooperate and end up twisted and fractured. The part is on one layer and the surfaces that get messed up in a “join” command are on another layer. I have the part file available for review and before and after images of the Join command. I did the “ClearAllMeshes” command and even "exploded the solid to surfaces. I rebuilt the surface with newly created curves and get the same result.

  2. Also there are curved surfaces, large fillets, manually created that end up split for no reason. Could you look at this and tell me what is going on? This is not a big concern as 1. is.

I have done a “check bad surfaces” for any red flags. There are none. The problem area is in a step between ejector and cover halves of a diecast mold to create a shut off condition.

I would like to create a solid model for 3D printing and for the tool house for molds.

Thank You


It is impossible to know what is causing your problems without more information.

Are you using Rhino for Windows or Rhino for Mac?

What exact commands are you using?

Can you upload the .3dm file, or a portion of it which has the problem? Use the “up arrow” on the line above where you type posts.

If you can not upload the file can you post a screen shot of the problem?

Rail Block - DMP.3dm (1.5 MB)
I have Rhino 3D for windows 8.1

I created the part as a solid model, initially.
I had to revise it with filleting and wall thickness changes.
I separated out the surfaces to modify and connecting surfaces.
I used the command “Join” to connect all the surfaces.
The before and after images show the surfaces affected.
I replaced these surfaces, all surfaces from scratch, not using any previous curves or surface edges. I did a ClearAllMeshes as well before Joining. I would like to put this in a solid even though I am going to split the part into 3 sections, ejector, cover and slide. I have created an “as cast” and an "as machined solids parts. Something is not working right in the joining process. Is there another way to create a solid without the Join command?

Thank You,


Hi Kimm,

I see two problems. The first is that your tolerance is too large. Some of the surfaces are only twice tolerance wide. Change to 0.001 and you will be better off. Now join and you will not get an invalid object but there will be a hole. That hole is there because there is no surface to fill it. Maybe you deleted it by mistake.

I changed the tolerance as you said and it joined to a perfect closed solid model. I shall make sure the tolerance is set to .001. I worked in what was called double precision in another unix based CAD program which went out to 16 place tolerance.
Thank You very much,


Great. I’m glad it worked for you.