Planar surface best fit through wriggly curves, what command?


#1

Hi,
V4
I have imported my fuselage work from a photogrammetry program into Rhino. The nature of the beast means lines are a little wriggly’ in places and I wish to best orient this fuselage using lines I know should be matching x y and z axes.

To do so, I need to place planar surfaces through pairs of lines , i.e same frame line on port and stbd for horizontal fit, or fuselage seam above and below fuselage for vertical fit etc .and have best fit occur to these wriggly curves.

Imagine a fuselage ‘stringer’, it heads fore and aft between the fuselage main frames, it has a slight manufacturers curve in aircraft plan view, but mine also has a slight wriggle along its length in aircraft side view !

What command should I use to fit a planar surface through these port and stbd stringer lines if they have designed planar curvature but also are a bit wriggly ?

I found rectangular plane through points tool, but I have wriggly lines. Maybe I have to spend time making points along my lines then select those ?

Once I have these indicators of vertical and horizontal created I then need to select these and do a best fit of this fuselage to vert and horizontal, best fit to x y and z axes in fact.

What is the best way of telling rhino to take all surfaces that should be parallel and in e.g. the yz plane and best fit the object to that orientation. then that done, to best fit the surfaces that should be in the xy plane to such without losing the first alignment ?

This done I then need to improve the lines and curves, I need to best fit a new curve to existing wriggly curve. For those with the planar surfaces there is a modelling aid there though projectToCplane wil also flatten anything.
What command to draw a new curve through a wriggly existing one ?

Steve


#2

If they’re wriggly “lines” then they’re not lines but probably NURBS curves, you might try turning on EDIT points (not control points) and run Plane through points with those; if there are not enough points for your taste, then use Divide instead and put as many points as you think you need per curve. That will get you a “best fit” average plane.

–Mitch


(David Cockey) #3

To find the plane which “best fits” the wiggly curve either turn on the edit points (not control points) as Mitch selected, or use Divide to create points along the curve. Then use PlaneThroughPt to create the plane.

If you want to make the curves planar you can use Project or Pull to move the curve onto the plane.

There is not a tool in Rhino to precisely best fit a “smooth” curve to a wiggly curve without user input. I’ve used Fair, Fit, Rebuild and RebuildCrvNonUniform to create smooth curves based on wiggly curves but it generally requires several tries.


#4

Hi,
Thanks for reply,
Ran command EditPtOn and my wriggly lines develop points.
Run command PaneThroughPt and it says select points, but I cannot drag selected these or even click select these when the command EditPtOn is asking me to. If I exit that command then I can select them all by dragging a selection box around them but I cant select them individually with a left mouse click, so how do I select these points on my wriggly lines when EditPtOn is asking me to ?

I then tried Divide command and thats good, I can select those for the PlaneThroughPt command and I get a planar rectangle form.

I shall post the send part of this as a new post as it may prove beneficial to users if not buried in this post.

it is :-

Once I have planar surfaces created, I see that they are a not quite aligned to 3D world planes, what is the best way of getting Rhino to re-orient these so that an average of those that should fit the YZ plane is used to best fit to YZ plane.
Ditto those for XY.
I need the aircraft fuselage to move along with the planar surfaces.

An ideal command would be something like my fictitious command BestFitPlanarSurfaces

…see separate post…BestFitPlanarSurfaces3Dworld

Steve