3D sketches constraint issue... again (sorry about that!)
You'll need to share the model. Export it as a .f3d file and attach it to the next post.
I did a quick test, just to see whether it does work as I expect it. While I don't understand what all these terms mean, I at least know what a ship looks like. So, I created a sketch for the keel, and a few sketches for sections along the length of the keel sketch. I used Project -> Intersect to project the intersection of the keel spline into each sketch, then snapped another spline to that point. I found that I could go back and edit the keel spline, and the intersections seem to update correctly. So, the basics work. Will need more info to go beyond that.
One question, though: When you say "I want to tweak the sheer line a little", I'm curious about that "tweak". If, by chance, you do any delete/recreate of that line, then I would expect the intersections to come apart, as they are tracking the actual curves selected. If it's not that, then it could be some other workflow difference.
Jeff Strater
Engineering Director
Oh, I see the problem. This is a Direct Modeling design. Sketch Projections (regular or intersections) never update in a Direct Modeling design. Use a Parametric (History-based) design, and things should work.
Jeff Strater
Engineering Director
@nicolas.leduc.mail wrote:
Time for me to start from scratch, I guess !
Yep, and while you're at it, use the least amount of spline control, points, and the least amount of profiles and rails you can get away with. I followed the link you provided and the approach with all these profiles will not result in a smooth loft.
Creating a boat hull with such drastic changes in curvature in a single loft is not something I'd advise. In any CAD software.
Your splines still have too many spline control points. You might be able to construct a loft but the surface quality will not be great.
All 6 sketch features in the timeline of your design are highlighted in yellow, indicating warnings.
Also, while one should never say never, I would never create a fit point spline with more than 2 points as a 3D spline. The curvature of such a spline is impossible to control.
If you want to loft from the top to the bottom (or vice versa) you need a rail on the XZ plane for the front and rear to control the loft.
You would first create the top and bottom profile.
Then the front and Rear Rails.
You would then create a couple of construction planes, and sketches for loft rails on those planes. You'd use the sketch->project->intersect function to project the points into those sketches where the loft profiles intersect those planes. You need to use those points to create the loft rails.
These errors are all relatively easy to explain:
The first two, I believe are probably caused by inadvertently selecting a Point when selecting a profile/section.
- Error: There must be at least one intermediate non-point profile for a loft.
- Error: A point profile can only be used as the first or last profile of a loft.
It is easy to do, especially in surface loft. You are trying to click on a curve, and unintentionally click on one of the fit points. Then you see a loft that goes down to a point:
If you select two of them as your profiles, you get the first error:
Similarly, if you inadvertently pick one for a middle section, you get the second error:
- Warning: The selected rail does not touch all of the profiles. (which is really odd this time).
I did not get this error with your design. I did, however, get a self-intersecting surface result:
that one is probably because of the curvature in the rails, but I don't know for certain
Jeff Strater
Engineering Director
Please share some images of the ship or boat in question. As I understand it, you already had some images inserted as canvases in your first model but removed them to save space. once we have the images we can provide better feedback and perhaps a screencast.
Until you have succeeded in creating a loft using your curves, you won't be able to fully understand what I posted. It requires some experience with the behavior of NURBS surfaces.
