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Collar

The collar is an important component to the Zellerfeld file submission process. It ensures not only proper printing structures to be made, but also structural integrity for the shoes during their lifespan.

 

COLLAR CHECK TUTORIAL

We know that passing the collar check can be a bit tricky so we created a tutorial video that shows you how to prepare the files in Blender. This process also works for the mesh surface checks as well.

 

COLLAR SURFACES

The collar surfaces are copies of shoe surface regions that separates the exterior from the interior of the shoe, THESE REGIONS ARE ALWAYS PRINTED ON IN CLOSED ZELLERFOAM.  

Collar check can handle multiple surfaces, which includes the foot entrance and any holes between exterior and interior of the shoe, for each surface will be checked:

  • Should not be watertight 
  • Should split the shoe in 2 parts (exterior & interior)
  • Can have 2 or more OUTLINES
  • IS A COPY OF A REGION OF SHOE SURFACE, SHARES THE SAME POLYGON FACES AS THE SHOE. 

COLLAR - CASE FLIPFLOP [UPDATED]

Flipflops always expect 1 or more surfaces for collar:

Similar to slide construction, the collar surfaces separate the shoe exterior from interior. [NEW] the surface should join in the direction of the footbed, stopping just above the footbed. 

  • Depending where it is connected, traps can have mesh or be fully closed. 
  • Update allows straps that join with footbed (no hole/cookie)

 

PREPARING SURFACES FOR COLLAR AND ZELLERMESH

Since the last update, uploaded surfaces now replicate the shoe’s mesh faces exactly — previously they could only be similar — giving you full output control and speeding up autocheck to run in only  30 seconds by submission. 

Here is 3 methods to obtain surfaces in the new standard:

METHOD 1 - Download CAD Helpers (Blender and Grasshopper)

Works if you already have surface files but don't pass the Collar Surface or TextureMap checks. In Blender, install the script (Edit > Preferences > Get Extensions > Install from Disk) as an extension, it adds the Zellerfeld menu in the side bar.

Open the menu and select the shoe, collar, and surfaces, then hit Extract. The script will automatically create new surfaces around the shoe at the distance you choose, if your surfaces are far from the shoe, you may need to increase the distance value. 

Check this video: 

Zellerfeld - Method 1 - Extract surfaces with Blender plugin.mp4

METHOD 2 - SUBD Edge loops - Start with a clean SubD model and make sure your face loops clearly outline each area that should become its own surface. 

After subdivided and triangulated in Blender, in edit mode press 2 for edges mode, with control pressed select edge loops. 

After selecting interior and exterior loops, go to Mesh > Split > Faces by Edges to split, then Mesh > Separate > By Loose parts will create the collar as a new model inside the blender. 

Check this video: 

Zellerfeld - Method 2 - Edge loop split in Blender.mp4

METHOD 3 — Cutting the Mesh — should only be used as a last resort. 

It’s mainly for decimated models where you need to create a cutting surface that divides the shoe into separate parts (interior, collar, exterior).

The tricky part is that after cutting, the shoe and the extracted surfaces must share the exact same faces. So once you export the separated surfaces as STLs, you must merge all the cut pieces back into the original shoe. This step adds any new faces created during the split back into the shoe mesh.

However, recombining the parts can introduce problems: the mesh may no longer be watertight. Cleaning the mesh can change face structure, which means the collar surface you exported earlier may no longer match. If that happens, you can use Method 1 to re‑extract the correct faces from the updated shoe mesh.

Check this video: 

Zellerfeld - Method 3 - Cutting mesh in Rhinoceros.mp4

KEEP IN MIND

  • Always triangulate meshes inside your CAD, exports can change face structure.
  • You can always run Method 1 afterward for perfect face matching.
  • Imagine the shoe as made of separate parts, which will simplify surface extraction.
  • Decimation is powerful but needs to be used wisely, only use it on the regions you actually need.

COLLAR INSTEP

Checks if the collar surface where the foot enters the shoe is behind the instep plane reference. This check helps to make sure the shoe stays on the foot when walking. Stay behind the plane!

*Not applicable to Flipflops!

COLLAR ROUNDNESS

Check if the collar surface is round - or free of sharp regions. 

in Blender: Edit Mode > Select > Select Sharp Edges (angle = 22.5°)

To ensure the collar surfaces are rounded you can create them by bridging the low-poly interior and exterior of the shoe. When subdivided it will automatically create a smoothly round transition!

Tolerance: Regions with less than 20 mm² will be ignored. 

 

ANKLE HEIGHT

Checks if the Collar region intersects the spherical region that represents the ankle. Stay below or go above this region!

Disclaimer: image is illustrative, may not represent current ankle-height requirements!