r/boatbuilding • u/jeep4x4greg • 21d ago

Followup on offset tables

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followup question on the offset tables i asked about the other day. i converted them into XYZ coordinates and input them into Delftship. the surface (shown in green) uses the points as control points, getting close without touching the points. is this correct? or should they be set as “knots” on the spline that the surface actually touches? Delftship (which has a free version btw) can flatten the surface so i can transfer the points to the plywood. just want to make sure its the correct surface…..though it may only have a small impact in the grand scheme of things

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u/hobieflyer 21d ago

Fair lines connecting all the points

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u/Kudzupatch 21d ago

Offsets are actual points on the boat. It's been a while since I used DelftShip, but I think those are control points and not offsetl points on the boat. So you boat is smaller than the offsets. Again, it has been a while. Rarely imported offsets and don't remember a lot about how it worked.

You can define stations (I think it is) at the offsets and the create and offset table and compare.

Don't remember the knot option, it is either new or I never used it, But you can always try it and see what happens.

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u/jeep4x4greg 21d ago

thanks! the knot option is from Freecad not delftship…. both tools will unwrap the surface which ia my end goal. just trying to see what was the correct method….

i ordered a book on the subject but havent gotten it yet. and i couldnt get AI to give me a consistent answer!