Re: transom and deck

[John R. Coil]

It sounds right that you’ve got to find intersections twice since you’ve two layers (hull and deck).

What I’ve found in my own experience is that when you intersect with multiple layers like this (I’ve usually got multiple layers too) is that near the transitions between layers the program does not necessarily create all the control edges you may need on some layers. I would guess that this is because some CPs which may have been used to help create subsequent faces in a different layer (like a deck fit to a hull) are co-joined to the later face but are actually a part of the earlier. For example, “Move” your deck up a foot (which you can always undo) and you’ll possibly find it assuming a humped shape as the CPs that are really part of the hull remain where they were but the control edges between them and the deck also remain. While I’ve not qualified the program’s behavior exactly it seems that it will miss putting that last control edge into the “newer” face in a different layer that connects to the CP in the “older” face in the original layer. The CP needed is usually there, though, as it was inserted as part of finding the intersection between layers for that layer.

So before I start deleting excess I find it necessary to create these missing control edges — their presence stops the program from deleting more than I want it to.

Sometimes you can have one of these missing control edges that is really small because of where you were intersecting layers — say if your curved surface passed very close to, but not exactly through, one of your CPs on the sheer line. If you find you’ve a problem area that wants to delete too much zoom up on the problem area after you undo the delete and see if there isn’t a missing tiny control edge to deal with first.

I hope that helps.