Can I draw a spline curve through specific points in BricsCAD?
Short Answer
Yes — in BricsCAD, you can draw a spline curve through specific points using the SPLINE command and choosing fit points, which is the most common professional method for creating smooth curves from known coordinates or snapped geometry. The curve may not match sharp corners exactly.
What You Need to Know Before
Warning: A spline created through fit points is mathematically smoothed, so small point spacing errors can cause the curve to bulge or overshoot unexpectedly. This is especially common when OSNAP picks the wrong nearby point or when points are not coplanar in 3D.
How to Draw a Spline Through Specific Points in BricsCAD
Command: SPLINE
Shortcut: SPL
Quick Steps:
- Start SPLINE from the Ribbon: Draw panel, or type
SPL. - Click each exact point the spline must pass through using Object Snap if needed.
- Press Enter to finish, then confirm the end tangent option if prompted, or press Enter again to accept the default smooth result.
- Start SPLINE from the Ribbon: Draw panel, or type
Use Object Snap toggles such as Endpoint or Node to place fit points accurately.
Variables & Settings
Key Setting: Object Snap (OSNAP)
Expert Setting: Turn on only the snap modes you need, such as Endpoint or Node, before placing spline points. Too many active snap modes can cause incorrect point selection and distort the spline path.
Why it Fails
Cause 1 (Geometry): Points are too close together or unevenly spaced, causing spline oscillation or unwanted bulges between fit points.
Cause 2 (layers/Locks): The current layer is locked, or the target points are on faded/overlapping reference geometry that makes snapping inaccurate.
Cause 3 (Command/Logic): The user mixes control-vertex expectations with fit-point behavior; a fit-point spline passes through points, but its tangency and curvature are automatically smoothed.
Quick Fix & Best Practice
Quick Fix: Turn on OSNAP, rerun SPLINE, and select only the exact fit points in order from one end to the other.
Manager’s Verdict: Use a fit-point spline when you need a smooth presentation or manufacturing guide curve through known points. Avoid it when exact segmented control or sharp directional changes are required; use polylines or arcs instead.
FAQ
Can I edit the spline after drawing it?
Yes, you can grip-edit spline points and properties after creation.
Can a spline pass exactly through every selected point?
Yes, with fit-point input, the spline passes through the selected points.
Can I convert a spline to a polyline in BricsCAD?
Yes, but the result is approximated and may lose smooth mathematical behavior.
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