I did a search for this and the most relevant thing I could find was the following thread. But there was never a resolution and that was for C3D 2009 so I'm hoping it's been fixed.
I have a surface that was created from my corridor and another that was created using a Grading Object.
Both have boundaries defined. Then I created a "Proposed Composite" surface and pasted the first two in. For the most part it looks good. But at one point, the triangles and contours cross the boundaries.
Don Ireland
Engineering Design Technician
I set the parking area and boat ramp surfaces to "Border Only" and changed the style to a heavly, light blue line. Here's a screen shot of the result. The contours are all from the pasted surface (Proposed Composite).
Don Ireland
Engineering Design Technician
the new composite surface will need its own boundary to remove the new lines created in between the two pasted surfaces. It is not a bug. this is the way the program normally works.
when new data is added to a surface, the program tries to connect vertices that are close to each other.