Offsetting surfaces with clean (non-intersecting) joints

Hi Yousef,

Discussion has veered away from your original request. But, if this is for a built structure, as Michael points out you will have to design the interfaces between the panels to give the support and weather sealing that your structure needs. Because your collection of panels is not regular you will have to consider each interface separately. There is no quick and easy way to do this.

I suggest creating, in a new layer, curves from the edges of each panel to use as guides for the layout of your interface structure. When you have the actual structure sorted out you can offset each edge of a panel inwards in the plane of the panel by whatever distance is needed to accommodate the interface structure. You can then offset the panel surface perpendicularly to create thickness. You will no longer get the troublesome intersections.

How exactly is that connected to what I said :smiley: @DanielPiker?
And it has to do with the software when talking about solid structure simply because Rhino isn’t very good at it. But that’s normal since it’s not made for that. That was my point.

@davidcockey, how many times have you seen ship/boat structure that connects over three planar plates in a circular (or aperture) fashion? That’s why there is a design before getting to the cutting. I don’t know what idiot could chop off a bulkhead into pieces then weld them back together :smiley:

What does that have to do with anything in this thread? Nothing anywhere about ships or boats. Nothing about designing bulkheads for ships or boats. The original question was about difficulties at the corners of triangular flat plates which are at angles to each other.


To which you say.

Daniel Piker’s statement is correct. If more than three planar plates meet at a point on one side, in general they will not meet at a single point on the other side.

Or do you disagree?


no, just saying it’s irrelevant for what I said. That it’s the software limitation.
Irrelevant due to how often it occurs in practice due to correct/incorrect design.

What is the software limitation - that If more than three planar plates meet at a point on one side, in general they will not meet at a single point on the other side? That is not a software limitation. That is basic geometry.

I’m done if you don’t understand what I’m saying it is not my problem.

Unfortunately, Revit does not calculate the joins between surfaces and it extrudes walls and roofs with a normal vector that is parallel to the z-axis and not parallel to the surfaces normal vector.

I understand what you are trying to say, but I’m not looking for this level of detail in my model, I want to obtain a flush relationship or if you would like to call it; a continuous surface, with no gaps in between.

It has to intersect in a point, if you have 3 faces. There must be at least one meeting point for the three planes to intersect at. Please support your claim with a picture or an example.

I understand the method implied, but it is a tedious and very detailed one. And I’m looking for a conceptual model with clean geometry.

What you are trying to do is harder to model and that’s why things don’t get built that way.

Hi Yousef,

If it’s conceptual maybe you could consider thickness unnecessary…


Incidentally, if you want to apply thickness it would be a good idea to clean up any existing anomalies in the model first as that will be easier than doing it later. At the moment there are a few panels that won’t join with their neighbours.

2 planes always intersect at a line.

3 planes always intersect at a point.

4 or more planes may or may not intersect at a single point. Any three of the planes will intersect at a point, but the point may be different for each set of three planes. This is the cause of your problems. Most of your nodes have more than 3 faces intersecting at the node.

@DanielPiker did not say 3 planes do not intersect at a point. He said:

I was just trying to figure this out myself and stumbled accross this old tread… realised that this conversation had an answer to the problem (within the chat) without anyone picking it up. A bit irrelevant now, but one way of doing this was to join all the surfaces together and turn them into simple mesh. Once you have the mesh then you offset that mesh into solid giving it a required thickness. Once you have a mesh with the thickness you change mesh to nurb, and you’ll get faceted polysurface with clean edges that you can take to Revit. I needed it for Revit too.