Every basic shape is also a starting point. With parametric controls, you can cut, hollow, twist, taper, and shear any prim into something entirely different -- and change your mind at any time.
The Build Panel's Shape tab gives you basic primitives -- boxes, spheres, cylinders, and more. But the real creative power comes from the parametric deformation controls: a set of sliders that reshape any prim without destroying or replacing it. Think of them as non-destructive sculpting tools. A box becomes a door frame. A cylinder becomes a spiral staircase. A torus becomes an arch.
The key insight: every change is reversible. Slide a parameter to zero and you are back to the original shape. There is no "undo history" to worry about -- the shape is always generated fresh from the current slider values.
Every prim is built from two things: a profile (the cross-section shape) and a path (the direction the profile is extruded along). A box has a square profile pushed along a straight line. A torus has a circular profile swept around a ring. The parametric controls let you modify both the profile and the path independently.
Profile controls change the cross-section: cut a wedge out of it, punch a hole through its center, or change the shape of that hole. Path controls change how the profile is extruded: twist it, taper it, lean it sideways, or remove a section of the extrusion entirely.
These controls modify the shape you see if you were to slice the prim in half and look at it head-on.
Removes a pie-slice wedge from the cross-section. You set a begin and end point, and everything between them is cut away -- like slicing a pizza and removing a piece. On a cylinder, this gives you a Pac-Man shape. On a sphere, it opens up a bowl or dome.
Punches a hole straight through the center of the prim, from top to bottom. The hollow percentage controls how big the hole is -- 0% is solid, 95% leaves paper-thin walls. This is how you make pipes, picture frames, tunnels, and hollow towers.
The hole shape does not have to match the prim shape. You can choose from four hollow profiles:
These controls modify how the cross-section is pushed through space. They turn simple shapes into complex architectural and decorative elements.
Removes a section of the extrusion itself. On a box, this slices it horizontally -- you might cut away the top third to make a low wall. On a torus, it removes an arc segment, turning a full ring into a C-shape or a half-circle. Set the begin and end points to control which portion is kept.
Rotates the cross-section progressively along the extrusion path. A box with 90 degrees of twist turns into a gentle spiral. Crank it to 360 degrees and you get a full helical revolution. You can set different twist values at the begin and end of the path, so the twist can accelerate, reverse, or stay constant.
Twist goes up to 360 degrees in either direction -- plenty for spiral staircases, twisted columns, candy cane stripes, and decorative railings.
Shrinks or grows the cross-section along the path. A box tapered on both axes becomes a pyramid. A cylinder tapered on one axis becomes a wedge or a funnel. Taper works independently on X and Y, so you can create asymmetric shapes -- narrow on one axis but full-width on the other.
Negative taper values flip the effect, making the top larger than the bottom. This is useful for creating flared bases and trumpet shapes.
Offsets the top of the prim sideways relative to the bottom, without changing the shape of either end. A box with shear becomes a parallelogram. Shear works on X and Y independently, so you can lean the top forward, sideways, or diagonally. This is how you make leaning towers, slanted roofs, and italic-style text blocks.
Leans the entire extrusion path sideways. Where shear offsets just the top, skew bends the whole path into a curve. This is most visible on torus-type shapes, where it tilts the ring into an elliptical orbit. On linear shapes it produces a subtle leaning effect.
Torus, tube, and ring shapes have a few extra controls because their path wraps around in a circle rather than going in a straight line.
| Control | What It Does |
|---|---|
| Revolutions | How many times the profile wraps around. At 1, you get a simple ring. At 2 or more, the ring spirals into a coil -- like a spring or a slinky. |
| Radius Delta | Makes the ring spiral inward or outward as it revolves. Combined with multiple revolutions, this creates spiral ramps and nautilus shapes. |
| Hole Size | Controls the thickness of the ring's cross-section on X and Y independently. A small hole size makes a thick, chunky ring. A large hole size makes a thin wire hoop. |
Here are common things builders make with parametric controls, along with the settings that produce them.
Start with a Box. Set Hollow to around 80% with a Square hollow shape. You now have a rectangular frame. Scale it to the size of a doorway and position it in your wall. The hollow creates the opening; the remaining material is the frame.
Start with a Box. Set Twist to 360 degrees (or more for tighter spirals). Make the box tall and thin -- the twist wraps it around itself like a ribbon. Adjust the width to control tread depth and the twist amount to control how many steps fit in one revolution.
Start with a Torus. Set Path Cut to keep only the top half (begin at 0.25, end at 0.75 -- experiment to taste). You now have a half-ring arch. Adjust the hole size to control the thickness of the arch, and scale it to fit over a doorway or bridge.
Start with a Cylinder. Set Hollow to about 90% (for thin walls) and Taper both X and Y to around 0.5. The cylinder narrows toward the top while staying hollow inside -- a funnel. Reduce the taper to make it more gradual, or increase it for a steep cone.
Start with a Box. Set Taper on both X and Y to 1.0. The box narrows to a point at the top -- a clean four-sided pyramid. Use lower taper values for a truncated pyramid (flat top), or taper only one axis for a wedge-shaped roof.
Start with a Torus. Set Path Cut to keep a quarter-arc (begin 0.0, end 0.25). Set a large Hollow with a circular profile. You have a 90-degree pipe elbow. Adjust the path cut range for different bend angles.
Parametric controls work on all of the standard primitive shapes. The effect of each control varies slightly depending on whether the shape uses a straight extrusion path (like a box) or a circular revolution path (like a torus).
Straight-path shapes (box, cylinder, prism) respond to twist, taper, and shear in straightforward ways -- the deformation happens along the height of the shape. Revolution-path shapes (torus, tube, ring, sphere) also support revolutions, radius delta, and hole size controls that only make sense when the path wraps around in a circle.
| Parameter | What It Does | Good For |
|---|---|---|
| Profile Cut | Removes a wedge from the cross-section | Pac-Man shapes, domes, open bowls |
| Hollow | Punches a hole through the center | Frames, pipes, towers, tunnels |
| Path Cut | Removes a section of the extrusion | Arches, half-rings, partial walls |
| Twist | Rotates the shape along its length | Spiral stairs, twisted columns, ribbons |
| Taper | Narrows or widens toward one end | Pyramids, funnels, wedge roofs |
| Shear | Offsets the top sideways | Leaning shapes, slanted roofs, parallelograms |
| Skew | Leans the whole extrusion path | Tilted rings, elliptical orbits |