Surface LIC, Clipping, and Animation

This chapter covers the signature Surface LIC flow visualization, clipping the geometry to inspect internal flow, and animating through saved time frames.

Surface LIC — The Signature Flow Visualization

Surface LIC (Line Integral Convolution) is the signature way to visualize flow on surfaces in LeaRes. It convolves a noise texture along the flow direction, producing streak-like patterns that reveal flow direction and structure directly on the geometry.

Enabling Surface LIC

1. Toggle Surface LIC on
2. The flow pattern is computed and rendered on the surface

Note: Surface LIC requires WebGL2 and a three-component vector field. While it is active, the scalar bar is hidden. Internally LeaRes builds the vector array under a GLSL-safe name (LICVectors) so the shader can use it reliably.

Surface LIC Parameters

Parameter	Range	Default	Effect
Steps	10–100	40	Integration steps along the flow; more steps give longer, smoother streaks
Step Size	0.1–2.0	0.5	Length of each integration step
Intensity	0–1	0.7	Strength of the LIC pattern over the surface

Tip: Increase Steps and tune Step Size for crisp streaklines that highlight separation and swirling flow. Use Intensity to balance the pattern against the underlying surface shading.

While LIC is active the colormap dropdown, log-scale toggle and range locker are hidden, and opacity is forced to 1.0 and locked.

Clipping the Geometry

To see inside the geometry, use the clipping flyout in the results toolbar.

1. Open Clipping
2. Drag the two thumbs of each dual-thumb slider — YZ, XZ, XY — to shrink the visible box along X, Y and Z. That is six clip planes in total, so you can cut from either side of each axis.
3. The clip is applied server-side and the frame is re-fetched, so expect a short delay after each drag

There is no arbitrary-normal plane and no invert option. Clipping is disabled while an animation is playing.

Animating Through Time

If the simulation was run with a frame granularity other than Last frame (Coarse, Fine, or Ultrafine — see Running a Simulation), multiple time frames are available.

1. Choose the frame range with the from/to dual slider
2. Use the playback controls to step or play through the frames, optionally with Loop enabled, or jump straight to Last frame
3. The visualization updates frame by frame, showing how the flow develops in time

Playback runs at roughly one frame per second and the speed is not adjustable.

Tip: Set Frames granularity to Fine or Ultrafine before launching a run when you intend to study the temporal evolution of the flow.

Troubleshooting

No Color on the Geometry

Problem: The geometry loads but appears uncolored.

Solutions:

• Confirm a scalar or vector field is selected
• Verify the job actually completed (reached 100%)

Surface LIC Has No Effect

Problem: Surface LIC is enabled but no streaks appear.

Solutions:

• Confirm a three-component velocity vector field is present
• If the Surface LIC toggle is missing entirely, your browser lacks WebGL2 or the required float-texture extensions — the control is not rendered at all in that case
• Adjust licIntensity upward and increase licSteps

Only One Frame Available

Problem: You cannot animate through time.

Solution: The run was likely launched with FramesGranularity set to Last frame. Re-run with Coarse, Fine, or Ultrafine to save multiple frames.

Summary

You’ve learned to:

• Load a completed simulation job into the 3D viewer
• Color the geometry by scalar and vector fields using LeaRes colormaps
• Use Surface LIC to visualize flow direction and structure on surfaces
• Clip the geometry to inspect internal flow
• Animate through saved time frames

Congratulations on completing the LeaRes engineering workflow tutorial series.