Vector Field / Velocity Overlay (GPU Particle Overlay)#
This section documents Cellucid’s GPU particle overlay for visualizing per-cell vector fields (e.g., RNA velocity, drift/displacement vectors) on top of an embedding.
Audience: wet lab / non-technical, computational users, power users
Time: 10–30 minutes (depending on depth)
Prerequisites: a dataset with at least one vector field for the current dimension (1D/2D/3D)
Important
The overlay is primarily a qualitative visualization of directionality. Always cross-check interpretation with your underlying velocity/drift methodology and uncertainty diagnostics.
Recommended reading order#
01_what_vector_fields_are_user_facing(what you’re looking at)02_enabling_overlay_and_selecting_field(how to turn it on reliably)03_core_parameters_document_exact_ui_labels(the knobs most users touch)05_performance_and_quality(if it looks wrong or runs slow)06_edge_casesand07_troubleshooting_velocity_overlay(when something breaks)04_advanced_parameters_document_every_setting(polish / cinematic tuning)
Pages in this section#
Mental model and what data is required for the overlay to exist.
Where the toggle lives, what disables it, and how the dropdown behaves across 1D/2D/3D.
Density, speed, lifetime, size, opacity, colormap, and LOD syncing (with exact UI labels).
Trail, bloom/HDR, color grading, and cinematic effects—every setting documented.
What scales with particles/trails, recommended settings by hardware, and “why it looks weird” checks.
Symptom → diagnosis → fix for the most common overlay failures.
Production checklist + capture specs for screenshots used in this section.