Hi Psygorn,

re:
> in MOI3D I get an artifact when I join two surfaces to make a solid in C-plane mode (otherwise (I mean
> in default coordinates) I don't get those artifacts) Could it be a bug?

It might be, can you please send me the file with the 2 surfaces in them before joining?

You can post it as an attachment here, or e-mail it to me at moi@moi3d.com .

Thanks, - Michael