Exoform

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Supports & loads

Fixtures, forces, Preserve, Obstacle, Shell thickness, Clearance — good vs bad.

Fusion Generative, Altair Inspire, and nTop all require a well-posed structural problem: something fixed, something loaded, and keep-solid / keep-out regions where manufacturing needs them. Exoform adds Shell and Clearance so those regions stay a useful thickness — not a one-cell ring.

Good vs bad tagging

Support · fixed500 Ndistinct faces — the load path can develop
Good
Distinct Support + Load faces — the load path can develop.
0 Nnothing fixedSupport ∩ Load on one face · force 0 N
Avoid
Missing fixtures, zero force, or Support∩Load on the same face.

Tool map

  • Support (fixed) — zero displacement (Fixed / Fixture). Where the part bolts or clamps to ground. A solid shell of the chosen Shell thickness stays locked here.
  • Load — total face force in newtons, axis or custom angles, uniform or linear distribution. Same Shell freeze depth as Support.
  • Preserve — must stay solid (Non-design). Mating faces, bosses, bearing seats, threads. Shell depth controls how far into the solid the freeze goes.
  • Obstacle — no material (Keep-out). Clearance for fasteners, cables, motion. Use Clearance (mm) for keep-out depth — mirror of Shell.

Shell thickness (holes & pads)

Support, Load, and Preserve faces freeze a solid shell into the part. Auto ≈ half a design voxel (one-cell). That is enough for the solver, but topology will still strip everything outside that shell — bolt holes can look “eaten.” Raise Shell (often 3–8 mm on brackets) so collars stay manufacturable. Whole-body Preserve still volume-fills and ignores Shell.

Shell 6 mm — collars stay solid and machinable
Good
Shell 6 mm keeps closed bolt pads around locked faces.
Auto (~½ voxel) — holes come back “eaten”
Avoid
Auto (~½ voxel) leaves one-cell rings; holes look skeletal.

Clearance (obstacle keep-out)

Clearance 8 mm — bolt head fitsthin void — head collides
Use Clearance so Obstacle faces reserve real fastener space — not just a paper-thin void.

Multi-load cases

Each Load can belong to a load case (case_1, case_2, …) with a weight. Topology minimizes the weighted sum of compliances — independent cases, not one summed force vector. Pre-check warns when multiple cases multiply FEA cost per iteration.

Required for Queue

  • At least one Support face.
  • At least one Load face with force > 0 N.
  • Do not put Load and Support on the same face — Fusion’s Pre-check rejects that pattern for good reason.

Load magnitude sanity

The default force is 500 N — change it. Compare to real service loads. Huge mismatches (1 N on a steel frame, or 1e6 N on a PLA bracket) create numerically weird or useless fields even when the job “succeeds.”

STEP faces vs STL paint

STEP: click CAD faces. STL: paint mesh regions — expect less precise BC application on curves. Prefer STEP when decisions matter.

Next: Design space · Checklist · Topology.

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