WHAT
Senior Graphics Architect Mittring an Senior Graphics Programmer Wright join us to discuss two new rendering features in Version 4.5 - Screen Space Subsurface Scattering, and Ray-Traced Distance Field Soft Shadows. As mentioned in the 4.5 preview notes, ray-traced soft shadows greatly enhance lighting visuals and the overall lighting workflow, and the new subsurface profile shading model enables more realistic skin shading and other cool effects. Come hang out with us!
Forward Rendering - are there still plans to provide forward rendering path, for materials ? Or migrating altogether to it ? The current deferred path impose few severe limitations (like it is hard to create custom lighting models, with material editor only).
Foliage rendering - any plans for specialized foliage shaders ? For grass (very simple and very fast), and for trees (more complex, but still cheaper than normal shaders) ?
I dunno if you can talk about it, but how is DirectX 12, integration into engine progressing ?
Any plans on implementing SSDO with GI ? I know screen space GI is not really good, but it would nice complementary solution for currently existing real-time GI.
Optimization in real-time rendering ? I won’t be pointing fingers because we all known what tech is leading in that aspect.
My question is will you guys focus on full real time rendering, after finishing tasks at hand ? Things like cached shadow maps (further cascades updated less frequently).
And of course immortal question, that I guess someone would ask anyway.
How is Dynamic GI progressing ?
Two things that I’m personally curious about.
How invasive is VXGI integration. Could it be provided as, easy-to-maintain feature like LPV is, or it needs much deeper integration into engine ?
Assuming that NVIDIa is willing to give away integration to all UE4 subscribers and you can talk about it. If no, please just say no (;.
I’ll just leave this here since it’s highly relevant to what will be discussed: Distance Fields in Unreal Engine 4 (Distance Field Ambient Occlusion & Ray Traced Distance Field Soft Shadows)
Please include a brief overview on how sss maps in U4 differ from UDK inscatter/absorb maps.
I only just got the hang of those maps…dont make me go crazy a 2nd time ^^,
Reason I ask this is because ive only seen 1 sss map slot “via google images” NO inscatter+NO absorb.
Examples with purely sss map breakdowns would be beneficial to more than 1 person im sure.
Could raytracing into a distance field be used for other effects in the future, such as reflective or refractive caustics? For example, could a car in a racing game create approximated reflections from the sun onto the road around it?
Are there limitations on the kinds of surfaces which can receive ray-traced area shadows? Can they cast onto skeletal meshes? What about translucent surfaces?
Are there any plans to support area shadows from objects which can’t currently be represented by a distance field? Could we, for example, create a small number of rigid geometric proxies linked to important bones which don’t render and only exist to create distance fields?
Do distance field area shadows have the same delayed, multi-frame accumulation as DFAO or are they always fresh with each frame?
Does the new subsurface scattering material have any way to simulate transmission from back-faces? If not, do you have any plans to support this in the future or would this require a forward rendering path?
Is there any active development of forward rendering? The road map has labeled it as “wishlist”; do you think this will ever become a priority?
Is there a we could see support for specific forward-rendered features such as anisotropic lighting and translucent specularity in the shorter term, with a return to all-purpose features such as the “light vector” node in the more distant future?
Is the temporalAA-based anisotropic specular from Brian Karis’s Siggraph presentation being considered as a viable solution for anisotropic lighting?
Are there any plans to improve the mesh distance field generation for thin geometry / small features in order to avoid holes? I’m well aware that you can increase the resolution but in many cases it would be sufficient to approximate thicker geometry.
Maybe add an option to let the user pick an additional, simplified mesh to generate the distance field for instead?
This is getting off topic, but are we likely to see any options for more detailed shadowing on translucency? The translucency lighting volume is okay for big irregular volumes like hanging smoke, but not detailed enough for more homogenous or opaque surfaces like sheer cloth, hair, thickly billowing smoke, or murky water. I don’t think you’d be able to see the effect of area shadows using the lighting volume in most cases.
@ - Any word on a fix for the screenspace SSS shaders in VR? As you can imagine, good SSS is a critical feature for VR games/demos with human(oid) characters, since the plastic-like skin is a real immersion killer.
That’s a shame about DFAO - I am currently using LPV and RTDF shadows and it works/performs splendidly, but is missing that extra oomph without the DFAO. Any it might get revisted after more VR optimizations are put in (such as passing both eye transforms up)?
Edit: Also any ideas why it doesn’t function at all? Is it just turned off because of the performance implications, or is that actually a bug? Basically when in stereo mode DFAO just turns completely off. If it’s just disabled when stereo is enabled, that would help me in testing to see if it’s even feasible to use it, since I could at least use what’s there and not have to contend with bugs right off the bat. I wouldn’t mind fixing it if it is a bug, either, and supplying a pull request. Knowing if it is or not without having to dig through parts of the engine I’m not familiar with would be really helpful though. Thanks!
Could it bit more expanded ? I mean do we really need parity between Forward and Deferred path ? Could have both, with forward being just simplified pass used for special cases, like translucency, or materials required custom lighting model (like foliage).
I dunno, if that wouldn’t break apart totally (very inconsistent lighting results).
Thanks. It is exactly my point.
I mean, most surfaces, can be done using deferred path, and where the forward+ is concerned, we probably doesn’t need those fancy features (like reflections on trees).
I personally see using forward path, for very specialized shaders, which can’t be really nicely made in deferred path, and won’t really benefit from deferred benefits.
I mean, I could live without them personally (;.
Unless you guys are looking forward (no pun intended), to drop deferred in favour of forward+.
What are per-object shadows ? It’s something along lines of screen space self shadowing ?
(joke)