Fast_checks

Houdini Digital Asset (fast_checks) for quick viewport visualization of drone show animation limits. Provides real-time visual feedback for speed, intersection distance, and acceleration checks directly in the viewport.

HDA: houdinitools/hda/fast_checks.hda

Also used inside:

/obj/TAKEOFF_AND_LANDING/Takeoff_sim/fast_checks
/obj/TAKEOFF_AND_LANDING/Landing_sim/fast_checks
/obj/Checker/fast_checks

Parameters

Parameter	Type	Default	Description
Exam Mode `exam_mode`	Menu	Speed	Which limit the viewport shows. Drones over the limit turn red; values are measured between neighbouring frames at the scene frame rate.

Speed

Hidden when exam_mode != 0

Parameter	Type	Default	Description
Speed Limit `SpeedLimit`	Float	4	Highest allowed drone speed in m/s, measured along the full 3D path.
Vertical speed limit `vertical_speed_limit`	Float	3	Highest allowed speed of climbing or descending, in m/s. Hidden when `enable_v_speed == 0`
Enable vertical speed limit `enable_v_speed`	Toggle	Off	Also mark drones whose vertical speed is over Vertical speed limit.

Distance

Parameter	Type	Default	Description
Distance `distance`	Float	2	Smallest allowed distance between drones, in meters. Each drone is drawn as a sphere of this diameter; drones closer than it to a neighbour turn red. Hidden when `exam_mode != 1`

Acceleration

Parameter	Type	Default	Description
Accel m^2 `AccelLimit`	Float	3	Highest allowed drone acceleration, in m/s². Hidden when `exam_mode != 2`

Other

Parameter	Type	Default	Description
High contrast `high_contrast`	Toggle	Off	Paint drones without violations dark gray, so the red violations stand out.

Usage

Select check type — Set exam_mode to Speed, Intersections, or Acceleration
Set thresholds — Adjust the visible parameters for the selected check type
Viewport feedback — Violations appear color-coded in the viewport: Red — above/below limit
Toggle contrast — Enable high_contrast for clearer visualization

In the full Checker HDA (Checker), the exam_mode is synced automatically when changing the parent's check type via the Python view() callback.

Video tutorials

Dronatello Course #10 — Checking Speed & Acceleration Limits with Fast ChecksDrones aren't magic — they have real physical limits on distance, speed and acceleration. We introduce the Fast Checks node, build an animation that intentionally breaks the rules, and learn to visualize problem areas directly in the viewport.