Roblox adds shapecast margins, size gradients and Studio visualization
Roblox upgrades shapecast accuracy and performance and adds shape controls. Retest collision-sensitive systems and use Studio visualization to inspect results.
Roblox has upgraded Blockcast, Spherecast and Shapecast, affecting teams building character controllers, combat queries and placement tools. Its October 28, 2026 announcement says the performance and precision changes are live today in Studio and published games without script changes. The release also adds margins, size gradients, transform and size overrides, and Studio visualization.
Existing queries need regression tests
According to Roblox, mesh casts now use the mesh’s exact collision geometry rather than a slightly reduced version. Returned Position, Normal and Distance values are also more precise. Roblox says the rewrite addresses invalid Blockcast positions, incorrect wedge and slope collisions, and contact points outside the swept volume.
Our recommendation is to retest movement and hit-detection code that depends on contact distances before changing its tolerances. Check mesh edges, inclined surfaces and floor seams this week. The automatic update means unchanged scripts can receive different results. Roblox reports faster execution, but we'd start by measuring query cost in your own scenes rather than treating its benchmark as your expected gain.
Inspect before changing query shapes
RaycastParams.Margin expands a cast and rounds its edges. SizeGradient changes the shape’s scale along its travel while leaving margin thickness constant. Roblox also says WorldRoot:Shapecast accepts optional cframeOverride and sizeOverride arguments, allowing predictive queries without relocating or cloning a template part.
We'd start by enabling Shapecasts under Physics simulation in Studio’s Visualization Modes, then inspecting a placement preview or ground check. The display shows the sweep, size changes and contact point. Our recommendation is to compare existing behavior with a margin-adjusted cast, checking whether earlier contact helps movement without rejecting intended placements or passages.