Capcom’s RE ENGINE workforce got down to carry path tracing into two transport titles without delay, Resident Evil Requiem and PRAGMATA, every with a special visible identification.
Over two years, the RE ENGINE workforce constructed a reference path tracer, validated its lighting towards frequent DCC path tracers, then scaled it right into a game-oriented model optimized for DLSS and constructed on the NVIDIA RTX Equipment.
The payoff: direct lighting now runs by means of the trail tracer as a substitute of shadow maps, the visible hole between gameplay and cutscenes is significantly lowered, and strand hair picks up real-time mild transmission in each titles.
The NVIDIA gaming workforce spoke with RE ENGINE concerning the transition from ray tracing to full path tracing, what it modified within the content material pipeline, and the place the renderer goes subsequent.
Why was now the time for Capcom to introduce path tracing into RE ENGINE in PRAGMATA and Resident Evil Requiem?
RE ENGINE has lengthy invested in rendering applied sciences, together with ray tracing, to create extra immersive experiences. Titles corresponding to Resident Evil Requiem and PRAGMATA more and more depend on lighting to outline the participant expertise by means of darkish atmospheres, advanced supplies, and pure reflections.
Our sport groups wished oblique lighting and reflections to be built-in naturally throughout environments slightly than adjusted individually. Advances in NVIDIA path tracing and body era applied sciences additionally made it reasonable to carry rendering high quality as soon as restricted to offline manufacturing into real-time video games.
We additionally wished to supply high-end PC customers with experiences that may solely be achieved on highly effective {hardware}.
The introduction of path tracing is due to this fact the results of years of R&D, inventive calls for from sport groups, the maturation of exterior applied sciences, and altering market situations all aligning on the similar time.
Seeing lighting naturally join throughout total scenes in growth builds was significantly impactful. Reflections and oblique mild, beforehand adjusted individually, started to kind a cohesive area, giving us sturdy confidence that next-generation real-time lighting was lastly clicking into place.
Now we have additionally continued to share information and practice groups past rendering engineers, together with technical artists and artists. To make use of next-generation lighting expertise successfully, the expertise itself shouldn’t be sufficient; the workforce additionally wants the manufacturing construction and experience to combine it into actual sport growth. We see path tracing not merely as a visible improve, however as an necessary turning level within the evolution of real-time rendering.
How did you evolve from a ray tracing pipeline to a path tracing pipeline throughout a number of titles?
The groups labored collectively for 2 years to enhance high quality earlier than the discharge of Resident Evil Requiem and PRAGMATA. We first developed a reference path tracer, then created a game-oriented path tracer optimized for DLSS Ray Reconstruction denoising. The reference path tracer was progressively refined by validating its detailed lighting conduct and bounce outcomes towards frequent DCC path tracers.
The sport model was then scaled all the way down to function effectively in real-time environments.
Technical artists additionally led the in-game integration, which allowed us to introduce the trail tracer into each titles on the similar time. When sure parts have been tough to help accurately, corresponding to clear lampshades constructed round blur filters, the groups shortly shared the problems and doable enhancements with all stakeholders. This helped carry path tracing to a secure, usable state within the titles.
How does the trail tracing implementation differ from earlier ray tracing renderers?
Beforehand, ray tracing was used just for oblique lighting. In PRAGMATA and Resident Evil Requiem, it is usually used for direct lighting. Character lighting particularly has improved considerably, creating extra dimensional shadows and oblique illumination.
Conventional ray tracing relied on shadow maps, which frequently suffered from restricted decision. Whereas this was much less noticeable in cinematics as a consequence of manually tuned shadows, the lighting high quality might really feel compromised throughout gameplay. As a result of path tracing is energetic always, the visible hole between gameplay and cutscenes has been significantly lowered.
How did you guarantee each ray tracing and path tracing might run throughout a variety of units?
The comparatively contained environments featured closely in Resident Evil Requiem and PRAGMATA labored to our benefit. Moreover, our growth setting, RE ENGINE, makes use of RayQuery-based ray tracing, permitting us to constantly validate ray tracing at any time. This established a powerful basis for working ray tracing throughout a variety of units.
Denoising is likely one of the key challenges of path tracing NVIDIA DLSS Ray Reconstruction supplies sooner and extra secure denoising than hand-written shader-based options and serves as a crucial basis for our implementation.
We additionally needed to optimize reflections and shadows for broken areas with lacking geometry. Within the earlier ray-tracing strategy, which used shadow maps, AlphaTest didn’t create a particular downside. With path tracing, nevertheless, producing smooth shadows requires evaluating cutout areas within the shader when a ray hits. Performing texture lookups for AlphaTest at each ray hit could be too costly, so we created a light-weight ScreenSpaceAlphaTest technique that compares the ray-hit place towards screen-space depth to find out whether or not the ray ought to cross by means of.
When utilizing NVIDIA RTX Equipment and DLSS 4, how do you handle sampling, noise, and denoising in advanced scenes?
For emissive samples, utilizing solely the outcomes of BSDF sampling causes contributions to build up solely on hits, which creates plenty of noise. To handle this, we use a devoted sampling construction for Subsequent Occasion Estimation (NEE). Moreover, to cut back noise in indoor areas the place IBL is dominant, we make the most of ReSTIR GI to pattern contributing paths. Quite than utilizing the implementation in RTX Equipment, we reimplemented ReSTIR GI ourselves primarily based on the printed paper.
How did path tracing change the content material pipeline, particularly for supplies and lighting in PRAGMATA‘s science fiction environments in contrast with the grounded realism of Resident Evil Requiem?
In each titles, path tracing improves international illumination and specular reflections, enabling higher-quality realization of every sport’s creative imaginative and prescient. For Resident Evil Requiem, as a result of the title locations sturdy emphasis on reproducing the true world, high-precision path-traced lighting significantly improves general scene consistency and spatial believability. It additionally made asset high quality and implementation points simpler to see, so we reviewed not solely lighting, but additionally asset manufacturing, implementation guidelines, and high quality verification. This allowed us to ascertain a growth workflow targeted on constructing high quality all through your complete content material pipeline.
Path tracing additionally works nicely with strand hair; real-time mild transmission by means of Grace’s hair contributed considerably to the sense of quantity and materials high quality.
For PRAGMATA, path tracing is very suitable with its hard-surface science-fiction environments, and high-quality reflections enhance the title’s visible high quality. As a result of floor precision, normals, and materials settings have an effect on the ultimate picture extra straight, reflection-aware asset manufacturing and high quality checks are extra necessary, evolving the content material pipeline in order that high quality is inbuilt not solely by means of lighting however from the asset-production stage onward.
PRAGMATA additionally makes use of strand hair: along with path-traced transmission, the title’s frequent three-dimensional motion and Diana’s lengthy hair assist make the motion really feel extra dynamic. Realizing Diana’s lengthy hair required overcoming hurdles corresponding to hair rely, joint rely, and physical-control optimization, supported by information amassed from Resident Evil Requiem and cooperation between the RE ENGINE and PRAGMATA groups.
For each titles, it was additionally essential to help not solely path tracing, but additionally current ray tracing and probe-based GI lighting.
What was probably the most important visible enchancment in Resident Evil Requiem when path tracing was enabled?
The sense of grounding. Correctly depicting the factors the place objects relaxation on prime of each other requires correct shadows and oblique lighting outcomes. Moreover, character faces particularly are the place these visible results are most distinguished. Now we have reached a degree of high quality that can not be achieved with out computing GI through path tracing. As well as, shadows created by oblique lighting give scenes a dimensional, grounded look that’s distinctive to path tracing.
This degree of visible high quality could be tough to attain with conventional rasterization strategies.
Get began with NVIDIA RTX Equipment
Try full path tracing in Resident Evil Requiem and PRAGMATA. NVIDIA RTX Equipment is the suite of neural rendering applied sciences behind this work, protecting path tracing, geometry dealing with, and neural denoising.
In the event you’re integrating path tracing into your personal engine or title, get began with RTX Equipment and discover the NVIDIA DLSS.
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