Changelog: v2.6

v2.6.1 (2026-09-13)

TCP viewer: restored panes auto-reconnect (--no-auto-connect / RAYRAI_TCP_VIEWER_AUTO_CONNECT=0); command-line endpoint applies to the first pane only.
TCP viewer: pane outlines/dividers drawn under popups.
Windows installer verifies all CMake package files are staged.

Tendons

World::addSpatialTendon, addFixedTendon, addTendonCoupling and get/remove functions; raisim::Tendon. See Tendons.
Spatial tendons through sites and anchors, wrapping spheres/cylinders, side sites, pulley branches; fixed tendons over joint coordinates.
Springs, deadband, friction loss, armature, length limits; Tendon::Drive actuation, setTension, setActuationForce; polynomial TendonCoupling.
Attach to articulated systems, rigid bodies, world anchors, deformable and granular particles; solved with contacts (no cost without tendons).
Wires (addStiffWire, addCompliantWire, addCustomWire) are now tendon wrappers: implicit springs, no longer reported as contacts, width 0 hides them.
MJCF <tendon> (spatial/fixed) and <equality><tendon> import.

World

World::captureCheckpoint / restoreCheckpoint for in-memory rewind.
World XML export/import covers simulation settings, all material properties, per-object tuning, mesh collision/CoACD options, articulated control state, sensors, deformable/granular objects and tendons; full-precision, locale-independent numbers.
Sleeping: default quietSteps 2 → 5, both thresholds must hold, tendon-linked bodies sleep together.
setStaticFrictionVelocityThreshold treats ≤0 as disabled; IMU noise defaults to none.
Contact solver cache-line layout (granular scenes 3–8% faster); repeated object removal is ASan-clean.

RaisimServer

launchServer binds before returning (correct getPort); tendons streamed; viewer can delete tendons.

rayrai

Tendons drawn automatically (getTendonVisual).
Faster PBR: instanced unshadowed primitives (1,024 boxes 8.2 → 0.56 ms), specialized depth prepasses (+14.5% on dense meshes).
Lazy camera targets and depth-only allocation (−69.5% VRAM for depth, −33% for RGB over 8 contexts); checker texture leak fixed.
Displaced heightmap normals; setKeyboardInputEnabled; fixed missing robot meshes under PBR and heightmap texture-unit clash.

TCP viewer

Simulate a dropped world XML or --simulate world.xml in a child process.
Scene editing (spawn, delete, export XML), Ctrl-drag interaction wire, Live Signals with CSV export, MP4/PNG recording.
File browser, camera presets, grouped object list, help panel, more render options.
Split panes (Ctrl+Shift+O/E/W) with a server discovery table; layout saved in ~/.rayrai/settings.yaml.
SimControlRequest renamed to ClientRequest.