Blockwork
After Igloo Inc
An igloo is a sphere somebody had to build out of blocks, and that constraint is the whole read. This is the construction taken off the ice and put on a plain sphere: courses of blocks laid on the surface, one shared breath running through all of them, a local response to the pointer, and the points and links drawn only where the pointer has been. Nothing on this page is lit and nothing is refracted. Drag any figure to turn it.
1 · Courses
A sphere cut into blocks the way masonry is: horizontal courses, each one a ring of quads. The count per course has to follow the cosine of the latitude, or every block near a pole becomes a sliver. Turn the cosine off and watch the poles fail.
2 · Breath
The breathing is one field, not per-block animation: a travelling wave in latitude that every block samples, plus a small phase of its own taken from its identity. A uniform pulse and a travelling wave are one term apart and they read as completely different things.
3 · The cursor is a direction
Blocks respond to the angle between their own normal and the pointer direction on the sphere, not to their distance from the pointer on screen. The wrong version is one checkbox away and it wakes the silhouette, where the cursor is nowhere near in three dimensions.
4 · Points and links
The lattice is drawn only on the blocks the cursor has woken, and a link exists only while two of them are near enough. Reach and neighbour cap look like the same control and are not: reach adds length, the cap adds density, and only one of them destroys the object.
What it actually does
- Blocks per course has to follow the cosine of the latitude or the poles crowd into slivers. It is the same reason a real igloo’s courses get shorter as they close, and it is one line.
- Each course rotates its joints by a fraction of a block so no seam runs pole to pole. The offset is worth a hash rather than a constant: a constant half-block offset builds a visible spiral instead of a bond.
- The breath is one field, not per-block animation. A single travelling wave in latitude, sampled by every block, plus a per-block phase from its identity hash. A uniform pulse reads as a scale keyframe; a wave reads as an inhale.
- The pointer is a direction, not a screen position. Response falls off with the angle between a block’s normal and the cursor direction on the sphere, so the far side stays asleep and nothing reacts through the body of the object.
- The push is springy rather than eased, so a block overshoots slightly on the way back. The surface settles rather than arriving, and that is the whole difference between a material and a value.
- Back-facing blocks drawn at low alpha before the front ones give translucency for free once a painter sort is already there. One number, and it is the entire ice read.
- Points sit on the block corners rather than at the centres, because corners are shared between neighbours and the eye reads them as a lattice lying on the surface rather than as labels on faces.
- The link test is on live distance, so connections form and break as the sphere turns under the cursor. Capping neighbours keeps it a lattice instead of a mesh.
What the rebuild taught
- The neighbour cap matters more than the reach. Raising the reach adds long links that read as noise; raising the cap fills the field in solid and loses the object underneath it. Cap first, then tune reach. This is the same conclusion the dust links in Axis Mundi arrived at from a completely different scene.
- Drawing the graph only where the pointer is doing something is the entire trick. A permanent wireframe is decoration; the same wireframe appearing under the cursor is a response, and it is the same geometry either way.
- The response has to be measured in the object’s own frame. Screen distance to the pointer looks right on the front of the sphere and wrong everywhere else, because it wakes blocks on the silhouette that the cursor is nowhere near in three dimensions.
- A sphere is the honest test case, not the easy one. An igloo has a floor, a door and a crown, all of which hide the places tessellation goes wrong. A closed sphere shows every seam and both poles at once.
- A painter sort and one alpha number bought the depth read here and no lighting model was needed, which is the same result the orbital field study reached from the opposite direction.
Rebuild
Four figures on one sphere. The courses, with the cosine rule and the joint offset both switchable so each failure is visible on its own. The breath, uniform against travelling. The cursor field, with the falloff and the spring exposed. And the graph, with reach and neighbour cap on separate sliders, because they do not do the same thing.