Ray Studio: Tracing Light Through Your Stone
Ray Studio is a separate modal viewer that traces individual light rays through your design, showing exactly where they enter, bounce, and exit — a diagnostic tool for understanding why a stone sparkles (or doesn't) in specific places.
Opening Ray Studio
Click Ray Studio in the toolbar (next to Frost Edges). A modal opens with its own 3D view of your current design, rendered as a translucent gray gem so you can see the light paths through it.
How a ray is traced
Each ray starts as a vertical line dropping straight down onto the crown, like a beam of overhead light hitting the stone:
- Entry: The ray refracts as it crosses into the gem at the table or crown, bending according to the material's refractive index.
- Internal bounces: Inside the stone, the ray travels in a straight line until it hits a facet from the inside. If the angle is steep enough, it undergoes total internal reflection (TIR) and bounces to the next facet — this is the same critical-angle physics covered in Refractive Index & Dispersion.
- Exit: Eventually the ray hits a facet at an angle shallow enough to refract back out into the air. The path stops there, with an arrow showing the exit direction.
Each bounce is capped at 16 reflections — if a ray somehow keeps bouncing past that (extremely rare in a well-formed design), the path is dropped rather than traced forever.
Firing rays
Three buttons control which rays you see:
- Fire Ray: Arms click-to-fire. With this active, click anywhere on the gem's crown in the viewport to drop a single vertical ray at that exact spot. Click again elsewhere to add another — they stack up rather than replacing each other.
- Fire Random: Drops 10 rays at random positions across the crown's footprint in one click — a fast way to get a general sense of where light escapes versus where it stays trapped.
- Clear Rays: Removes every ray you've fired, so you can start fresh.
Tip
Orbiting the view (click-drag) while Fire Ray is armed won't accidentally fire a ray — Ray Studio only fires when your click barely moves between press and release. A real drag is treated as orbiting, not firing.
Reading the result
Rays are drawn in orange. A line segment marks each leg of the path (the entry ray, each internal bounce, and the final exit leg). An arrowhead marks the incoming ray and the final outgoing ray, so you can tell the direction of travel at a glance.
Turn on Show transmission angle (in the footer) to label each exit point with the angle, in degrees, between the exiting ray and the facet's surface normal — useful for confirming a ray is exiting steeply (more sparkle-like) versus grazing out at a shallow angle.
View controls
The same four preset views as the main viewport — Iso, Top, Bottom, Front — are available in Ray Studio's own button row, and you can click-drag to orbit freely, independent of the main editor's camera angle.
Why this matters for your design
If Fire Random shows most rays bouncing around several times before exiting through the crown, that's a well-cut stone returning light back to the eye. If many rays punch straight through the pavilion on the first or second bounce, that's windowing — the pavilion angle is too shallow for the material's critical angle, and you're seeing through the stone instead of sparkle. Compare what you see here against the windowing warning banner described in Refractive Index & Dispersion.
Closing Ray Studio
Click the X in the top corner, click outside the modal, or press Esc. Your fired rays are cleared when you close the dialog — reopening Ray Studio always starts with a clean slate.