DCC production guide
CAD NURBS STEP IGES Solid Repair Guide
Direct answer: CAD import review starts by checking whether the model is a Closed Solid with consistent Boundary Representation data or a loose surface set that must be repaired before meshing. STEP and IGES often arrive with different levels of reliability, so the receiving DCC must verify topology and tolerance explicitly.
Boundary RepresentationClosed SolidIGESSTEPStitch SurfacesTolerance
Read the source correctly
Boundary Representation means the file carries trimmed surfaces, edges, and topological relationships rather than only triangles. If the import loses that structure too early, repair becomes harder because tiny gaps and flipped trims are now buried in a polygon mesh.
STEP versus IGES expectations
STEP usually preserves product solids and assembly-style exchange more predictably. IGES often arrives as loose surface patches that still need Stitch Surfaces cleanup. Neither format is automatically safe; both need inspection of seams, patch continuity, and missing trims.
Tolerance is not cosmetic
Tolerance controls whether neighboring surfaces are treated as joined. Too loose and holes disappear by collapsing detail; too strict and a visually closed part remains open. The correct value depends on model scale, manufacturing source, and how much downstream simplification is acceptable.
Solid repair checklist
Confirm whether the part is a Closed Solid, whether stitched seams create non-manifold edges, whether tiny sliver surfaces should be deleted, and whether the final mesh conversion preserves sharp industrial edges. After meshing, recheck shell thickness, open boundaries, and shading normals.
Worked example
A consumer product handle imported from CAD may look intact in shaded mode while several seam edges remain open. Stitch the surfaces with a documented tolerance, delete sliver patches inside the grip, convert to mesh, then compare the meshed silhouette with the original NURBS curves before approving game-ready cleanup.
Multilingual production terms
This table is most useful when a CAD handoff has to separate solid-model facts, surface-stitch repair work, and tolerance decisions across teams.
| 中文 | English | 日本語 | Workflow usage note |
|---|---|---|---|
| 边界表示 | Boundary Representation | 境界表現 | Topological description of trimmed surfaces, edges, and faces. |
| 闭合实体 | Closed Solid | 閉じたソリッド | The model encloses volume without gaps; required for printing and Boolean ops. |
| IGES | IGES | IGES | Exchange format that often arrives as loose surface patches needing stitch repair. |
| STEP | STEP | STEP | Exchange format that usually preserves product solids and assembly structure better. |
| 曲面缝合 | Stitch Surfaces | サーフェス縫合 | Join neighboring patches within a tolerance to close gaps and build solids. |
| 公差 | Tolerance | 公差 | Numeric gap threshold; too loose warps detail, too strict leaves seams open. |
Related pages and next step
Open SEELE AI workspaceFAQ
Why does a part look closed but still fail solid checks?
Because shading can hide micro gaps, broken trim loops, or unstitched surface boundaries that only appear in topological validation.
When is IGES still acceptable?
It is acceptable when the receiving team expects surface repair work and the part does not depend on a perfectly preserved solid history.
How should tolerance be documented?
Write the numeric tolerance used for stitching or healing alongside the imported file scale so another reviewer can reproduce the result.
What proves the repair is done?
A successful solid or surface validation pass, a clean mesh conversion, and a silhouette comparison against the original CAD shape are strong proof.