Checker

Houdini Digital Asset (checker) for validating drone show animation data loaded from an Alembic cache. Runs proximity, speed, and acceleration checks on drone trajectories and prints violation reports.

HDA: houdinitools/hda/checker.hda

Parameters

Setting

ParameterTypeDefaultDescription
Abc path abc_pathFile—Alembic file (.abc) with the show animation to check. On selection the playbar range is set to the length of the file, starting at frame 1.
Reload Geometry reloadButton—Read the Alembic file again, after it was overwritten on disk.
Sample rate sample_rateInteger6Check every Nth frame: 1 checks every frame, 6 every sixth. Higher values run faster but can miss short violations; speed and acceleration are measured between the sampled frames.

Checks

ParameterTypeDefaultDescription
Check type check_typeMenuDistanceWhich limit to check and to show in the viewport: distance between drones, speed or acceleration. Check prints violations of this limit only.
High contrast high_contrastToggleOnPaint drones without violations dark gray in the viewport, so the red violations stand out.
Min distance m min_distanceFloat2Smallest allowed distance between any two drones, in meters. Closer pairs are reported. Hidden when check_type != 0
Exclude starting positions exclude_starting_positionsToggleOnLeave out of the distance check drones standing on the ground (lower than 1 cm), so the tightly packed takeoff grid is not reported. Hidden when check_type != 0
Max speed m/s max_speedFloat5Highest allowed drone speed in m/s, measured along the full 3D path. Hidden when check_type != 1
Max vertical speed m/s max_vertical_speedFloat3Highest allowed speed of climbing or descending, in m/s. Hidden when vertical_speed_limit == 0 or check_type != 1
Vertical speed limit vertical_speed_limitToggleOffAlso check the vertical speed against Max vertical speed. Hidden when check_type != 1
Max acceleration m/s^2 max_accelerationFloat3Highest allowed drone acceleration, in m/s². Hidden when check_type != 2
Check run_checkButton—Run the selected check over the whole animation and print the table of violations to the Houdini console.

Advance

ParameterTypeDefaultDescription
Log path log_pathFile—Folder for the full log. The file name log.txt is appended to this path as is, so keep the trailing slash.
Write full log to file newparameter2Button—Run all checks (distance, speed, vertical speed, acceleration) and write every violation to log.txt in Log path.

Usage

  1. Load animation — Set abc_path to an Alembic .abc file containing drone animation and click Reload Geometry
  2. Configure sample rate — sample_rate controls how many frames are checked (default 6 = every 6th frame)
  3. Select check type — Use check_type to choose Distance, Speed, or Acceleration
  4. Set thresholds — Adjust the visible parameters for the selected check type
  5. Run — Click Check — violations print to the Houdini Python console
  6. Save report — Set log_path and click Write full log to file for a detailed log

Video tutorials

Dronatello Course #25 — Validating Your Show: Distance, Speed & AccelerationA finished simulation still needs validation. We use the Checker node to run distance, speed and acceleration reports, learn how to read violation data, and pinpoint exactly where and when problems occur.
Dronatello Course #29 — Final Validation Pass Before Show DeliveryOne last, crucial check on the complete show. We run distance, speed and acceleration validation on the full sequence, excluding grounded drones from collision checks, to confirm the show is ready for final touches.