I’m trying to draw over a scan. (Or actually 2 aligned scans). My strategy is to first replicate the outer shape as closely as possible, and then apply some cuts and fillets to get a nice result.
The tolerances don’t have to be exact, but it needs to look like the original, and I need to get a printable object in the end.
The problem:
I’ve drawn a few profiles over the scan and lofted them, but the result looks pretty ugly.
The profiles are all quite similar (same number of control points and same general shape). The seam points were also nicely aligned.
My questions:
Is a loft the best way to go about this? If not, what is? I’ve also tried a sweep with a simple straight rail. I’ve had success with NetworkSrf before, but that doesn’t seem appropriate or straightforward here.
I actually tried a completely different approach first. Since the scans looked quite good, I tried to “blend” them together and then make some small adjustments on the resulting mesh. It didn’t work because I couldn’t blend/combine the meshes into one clean outer shell… Could this strategy work in Rhino? Or maybe using other software?
It helps to think about the nature of the shape and how your curves fit into that context. The object is overall quite rectangular so you want to end up with isocurves that follow that form. Even if you get side surfaces that follow your initial curves, you will have problems working the top and bottom if you do not. For example:
In this section you have a couple of sets of control points that are not conducive to a good flow over the top. If they are straightened out like the red markers things will work better.
To do this modelling in Nurbs, rather than trying to loft a continuous ring, I would aim to set up primary surfaces for the four sides, top and bottom, then work to round off the corners. For the sides I would start with vertical rather than horizontal sections.
However, as this is a soft shape I would suggest using Subd rather than Nurbs. In particular, the ability to sculpt Subd and drag it dynamically into line with your scans is pretty invaluable.
Thanks for the pointers. I’ll try to put your advice into practise, but It’ll take me a few days I suspect I may come back with more questions after that!
Hello- if you do this with surfaces, I would try to break the object up into simple more or less geometric underlying shapes and build those, then connect with transitions surfaces. The top for example, looks like it is probably a plane, split into two pieces, one on each side. The side4s may also be planes. The middle looks like it is an extrusion of simple curves-
I may come back with more questions after that!