Path tracing
A form of ray tracing that averages many randomly sampled light paths per pixel to simulate lighting physically.
How it works
Instead of tracing one neat reflection per surface, a path tracer picks random bounce directions according to each material's properties. One path per pixel looks very noisy. Hundreds or thousands of paths per pixel average out into a clean, realistic image. This is called convergence.
Strengths
Path tracing handles effects that are hard to fake, such as light bouncing from a gold band onto a diamond, soft shadows under a ring and caustics, the bright patterns of light focused through a gem onto a surface. Offline renderers such as V-Ray, KeyShot and Blender's Cycles use ray and path tracing for this reason.
Costs
The price is time and noise. Jewelry is one of the hardest subjects to converge, because tiny bright highlights and long chains of reflection inside gems need many samples. Denoisers help, but they can also blur fine pavé detail.
When you need it
For hero campaign images, print and close-ups where every caustic matters, an offline path tracer in skilled hands is hard to beat. For catalogue images, marketplace listings and social video across many products, a real-time studio that shows results immediately is usually the better use of time. Many jewelers use both, real time for volume and offline rendering for a few hero pieces. Our comparisons cover the trade-offs in detail.