Opening / navigating a heavy 3D DWG (e.g. a BIM model with ~10k ACIS solids)
was effectively frozen. Several independent costs, all addressed here:
- Face3D edge/fill buffers were re-uploaded on every camera move (keyed on
camera_generation). They are world-space and selection-independent, so gate
them on (geometry_epoch, fill_mode) instead — a pan no longer re-walks every
wire.
- Solid meshes were drawn one buffer + one draw call per solid (~10k draws/
frame), which strangled the GPU front end. Concatenate every solid's LOD0
into a few large buffers (split only to stay under the 256 MB buffer cap) and
draw the whole set in a handful of calls. Built once per geometry epoch, so
selection / hover never re-pack it.
- Selection / hover highlight is now a small tinted overlay of just the picked
solids, drawn last with an Always-depth pipeline so it shows on top even when
the solid is occluded — instead of re-tinting and re-uploading all meshes.
- Hover / pick hit-testing scanned every triangle of every solid each move
(seconds on a heavy model). Add a 3D-AABB screen-rect broad phase
(MeshLodSet now carries z_aabb) and reuse the renderer's cached expanded mesh
set, so picking is O(solids) cheap projections plus the few solids actually
under the cursor.
- Block-internal hatch hit-testing exploded every INSERT on every hover.
Cache the result per geometry epoch and skip blocks that contain no hatch.
- Curved-surface (cone/sphere/torus) tessellation tolerance is now radius-
relative (CURVE_REL_TOL) so a cylinder's facet count is size-independent and
matches the circle/arc wire tessellation, instead of exploding on large radii.
Also adds docs/tessellation.md mapping every EntityType to its tessellation
path (truck B-rep vs truck curve topology vs direct).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
