Last preparation and flattening

A very important step in the digital creation process for footwear is the process of cleaning a last and flattening it. This workflow will start from a scanned last and will end up with a remeshed last and its flattened version.

We begin with a last like the one in the picture:

If you are using Rhino 8+ you can use the _Shrinkwarp command to clean the geometry. This gives you a nice mesh that will be better to deal with when remeshing.

After the mesh is cleaned with B_DrawCrvOnMesh command you can mark the last on the important parts where you want lines to be respected. This will be used later for the remeshing that will drive the edge lines of the eventual quad mesh.

We typically suggest to use the following parameter when performing eh _QuadRemesh command, which is the next step in the workflow. This is a standard feature of Rhino since 7 and can be controlled via curves. We suggest to use the previously created curves to generate edge loops so you will have some nice seams to cut the mesh with.

Once the remeshing is done you want to unweld the parts of the last you want to be disconnected for the flattening. In our example here we are going to flatten the vamp as one piece and the strobel down. So we can use the _UnweldEdge command to disconnect the edges that we want to be cutting seams for our mesh.

After our mesh has been unwelded properly we want to use the B_Unwrap command from either the toolbar or the UV editing panel. Here you can set several options on how big the canvas size should be and how many iterations to use. You should keep the option Divide=SplitAtDoubleEdges to get the proper split on the edges that we unwelded.

Once we have the mesh unwrapped we can either keep it as texture coordinates or we can easily add that to the document with the option "Add to document" from the UV menu or the B_AddUvtoModel command. Finally we will have a clean last and its flattening in our document.