Hello,
I am having trouble getting this polysurface or even the profile curve to “unroll” flat (2D)
I have tried Unroll, Smash, Squish, 2D layout, ect, everything I can think of and read all the other related topics here with out any luck. Even tried cutting the part in 4 sections and doing each one at a time.
Basically I just need the surface or even profile curve to unroll / lay flat so I can use the 2D as a starting point to build my 3D from.
Attached is the 3D file and a pic of part I am trying to make. It is a foam insert for a motorcycle saddlebag that gets stuck
onto inside of saddle bag.
I have already made two versions of this part but was able to scan sample parts while laying it flat. For this version I scanned the inside of the saddlebag and created the polysurface to work from.
Thank You in advance.
Foam Insert.3dm (3.9 MB)
The fundamental issue is your object is a polysurface with 581 surfaces, and the surfaces appear to be degree 4 with 8 control points in each direction.
UnrollSrf, Smash and Squish do not like polysurfaces with large numbers of surfaces.
How did you create the surface? If you used MeshToNURB all it does is replace every mesh face with an individual surface. For situations like this the resulting polysurface is rarely useful.
Why degee 4 with 8 control points?
Assuming you started with a mesh you may be able to use Squish on that mesh.
You may need to create a surface with the minimum number of control points needed to represent the shape, preferably starting with the mesh or point cloud from the scan. There is not a quick process to do so.
Thank you for the response and information David.
I scanned the part with a Peel 3D Scanner, it creates a mesh then you can “auto create” the entire mesh into a polysurf. Or manually select points on an area of the mesh and create a polysurf of that feature.
When creating the polysurf I can set the parameters to number of control points and approximate number of patches. That is where the 8 control points comes from and I am assuming the 4 degree is related to the number of patches. I can set the control points lower and still have “close enough” data for this particular part.
Yeah I thought about creating surfaces from the mesh or even the polysurf but it does take a lot of time.
Since I really only need the profile curve of this part to lay flat, would there be an easier process to accomplish that? For example recreating the profile curve with less control points using “interpolating points” then try and get that to lay flat?
Thanks again, I appreciate the help
The shape is not developable, and cannot be unrolled flat without distortion. That’s how the geometry works. Smash or Squish will unroll/flatten non-developable surfaces with distortion, and Squish provides some control over how the surface distorts.
A curve by itself cannot be unrolled or flattened, beyond simple operations such as projecting the curve onto a surface. A surface is needed.
It does take time, but can become faster with practice
Depending on the accuracy required you could create a simplified surface.
I ended up sectioning the polysurf and making new surfaces then
unrolled those, worked good enough for what I needed.
Thanks again!
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