Rhino 3D Tip: Project vs Pull: Curve Transfer Best Practices

Transfer curves, points, and annotations onto complex geometry with confidence by choosing the right tool: Project or Pull. Knowing when to use each delivers cleaner trims, reliable panel lines, and accurate fabrication guides.

• Project: Casts geometry in a single, consistent direction—typically the active view’s CPlane Z—onto surfaces, polysurfaces, or meshes. Best for “from-above” or “from-side” workflows where a uniform direction is essential.
• Pull: Maps geometry to the closest points on a surface, polysurface, SubD, or mesh. Ideal when you need a curve to hug the shape, even on steep areas where a directional projection would miss or distort.

When to use Project

• Creating trim lines from orthographic sketches (Top/Front/Right) for clean, predictable sections.
• Panel layouts or graphic inlays aligned to a manufacturing direction (e.g., laser marking from Top view).
• Projecting jig holes or assembly guides from a drawing plane onto a part.

When to use Pull

• Wrapping logos, seam lines, or stitching paths so they “stick” to curved bodies.
• Deriving surface-following guides for sculpting, SubD retopology, or zebra-line references.
• Transferring curves to mixed curvature areas where a single projection direction fails.

Core workflows (fast and reliable)

• Project workflow:
  1. Set the active view you want to project from (e.g., Top).
  2. Run Project → select curves/points → select target surface/polysurface/mesh.
  3. Keep DeleteInput=No to compare before/after and validate.
  4. Use Trim or Split with the result; then SimplifyCrv if needed.
• Pull workflow:
  1. Place your driving curves near the target geometry.
  2. Run Pull → select curves/points → select target.
  3. Inspect for tiny kinks on tight corners; use FitCrv or Rebuild if required.
  4. Proceed to Split/​Trim or use as path guides for paneling or engraving.

Quality and predictability tips

• Decide by intent: choose Project for directional intent; choose Pull for surface-hugging intent.
• Reduce curve complexity before transfer: Rebuild or FitCrv produces cleaner, lighter results.
• Check tolerances: set appropriate Absolute tolerance in Document Properties before heavy transfers.
• Validate outcomes: use Analyze > Curve tools to find self-intersections or tiny segments after transfer.
• Meshes vs NURBS: both commands work on meshes; however, expect faceted outcomes on coarse meshes—consider QuadRemesh or refine the mesh first.
• After trimming with projected/pulled curves, run ShrinkTrimmedSrf to keep models tidy.

Troubleshooting

• Nothing appears? Switch to the view you intended and re-run Project (the direction is view-dependent).
• Unexpected splits on polysurfaces? Try Pull for closest-point mapping or pre-Join faces if applicable.
• Deformed results on steep areas? Prefer Pull, or break the curve into logical segments and transfer in parts.

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