Tutorial 3: Shaping the Profile Spline

Step 1

Understand the sweep concept

The profile spline defines a radius at every height. The cross-section shape (circle, polygon, etc.) is scaled to match that radius at each vertical slice, then all slices are connected to form the mesh surface. Think of it like a cookie cutter being pushed through a vertical guide rail.

Step 2

Build a bottle shape

Set Total Height to 150 mm and create 5 control points:
1. Bottom — radius 35 mm (⌀ 70 mm base)
2. Point at 10 mm (height) — radius 35 mm (straight cylinder base section)
3. Point at 60 mm — radius 35 mm (body continues)
4. Point at 90 mm — radius 15 mm (narrow neck)
5. Top — radius 18 mm (slight rim flare)

Set points 2 and 3 to Sharp mode for a clean cylinder section. Set point 4 to Smooth mode for a flowing shoulder-to-neck transition.

Step 3

Observe polygon + profile interaction

Switch to a Hexagon cross-section with your bottle profile. Notice:
- The hexagonal shape scales with the radius at every height
- The shoulder section smoothly transitions from large hexagon to small hexagon
- The flat sides of the hexagon remain flat at every height — only their size changes

Step 4

Observe Sine + profile interaction

Switch to Sine with 6 Lobes and moderate amplitude. With the bottle profile:
- The lobes are large on the body section (wide radius)
- The lobes shrink on the neck section (narrow radius)
- The transition in the shoulder area shows the lobes gradually reducing in size

This automatic scaling means your cross-section detail is always proportional to the object size.

Step 5

Create effect-friendly regions

Design a profile with distinct zones:
1. A flat, cylindrical section in the middle (constant radius over 40+ mm) — effects like waves and knurling look best on flat, even surfaces.
2. A curved section at top and bottom — effects follow the curvature, creating organic flowing textures.

This zoned approach gives you clear regions for different effects (covered in later tutorials).

Step 6

Experiment with proportions

Try two extreme profiles:
1. Wide and short — Total Height 30 mm, radius 60 mm. The mesh looks like a plate or shallow bowl.
2. Tall and narrow — Total Height 200 mm, radius 15 mm. The mesh looks like a column or candlestick.

Notice how the mesh quality distributes differently. Tall, narrow objects may need higher V (vertical) resolution. Wide, short objects need higher U (circumferential) resolution.

Step 7

Create inward curves

Design a profile where the radius decreases toward the top, then increases again (like an hourglass):
1. Bottom — radius 30 mm
2. Middle (50%) — radius 12 mm (narrow waist)
3. Top — radius 30 mm

Set all points to Smooth. The mesh shows a smooth hourglass shape. This works well for decorative objects and will accept effects gracefully because the surface normals change direction at the waist.

Step 8

Load a profile preset

Use the Presets dropdown on the profile editor to load a starting shape (Classic Vase, Cone, Funnel, Cylinder). Then customize:
1. Load Classic Vase — modify the belly radius and neck position
2. Load Cone — add a point to create a stepped cone
3. Load Cylinder — the simplest base for seeing effects clearly

Presets replace your current profile but can be undone (Ctrl+Z).

Step 9

Use the Profile Points table

For objects with specific dimensional requirements:
1. Open the Profile Points table below the canvas
2. Type exact ⌀ mm values for each point
3. Type exact Height mm values for interior points
4. Check the Layer column to verify alignment with slicer layer heights

This gives you a mesh with precisely controlled dimensions.