[UNREAL] Hologram Shader
This shader was created as an experiment to port a shader from a non-RT engine (redshift) to test the viability of unreal vs more traditional VFX production renderers. The final version of the shot is included at the bottom for comparison.
The Unreal version was fairly successful but due to certain limitations it is not feature complete compared to the final version. The main missing component is a way to replicate Redshifts RaySwitch node. RaySwitch was used throughout the final version to selectively dim the shader that is being viewed though it’s own transparency. This allowed more control over the brightness values of overdrawn geometry to maintain a more readable profile of the geometry. That combined with the fact that the unlit addative shader model is not visible to lumen reflections so the hologram does not show on the glossy floor at all. bummer.
One main advantage of the Unreal port was actually the unlit additive shader model. Whereas Redshift had a limited transparency trace depth that dramatically increased render time as the trace depth was increased, Unreal didn’t need this adjustment and would draw all of the geometry the shader was applied to no matter how many levels of overdraw. With a fairly complex model like this vehicle; this was actually a huge benefit.
Shader Features:
Procedurally animated scanline, noise, and displacement effects
Backface intensity masking
Curve atlas driven pseudo-fresnel falloffs
Curvature masking to suppress fresnel highlighting of large flat surfaces at shallow angles
