Universal Pipeline Raytracing ETA ?

Heya,

Wondered when the ETA for Universal Pipeline support for raytracing is (rough ballpark is fine)... I assume it's coming because it's not tied to HDRP at all API-wise, and it seems like a perfect boost for titles that are being ported from Universal / LWRP upward, adding much needed quality for ports with pretty much a few clicks. To me this is a very good improvement.

If it's not coming then please insert confused.gif of choice

 

(probably fastest way to shift folk from builtin to URP too)

 

Would be interested in this as well. Maybe the URP section would be a better place to ask for this?

 

Feel free to ask there too if you like.

 

I think we will get news when they will officially unveil RTXGI beyond stage demo of "upcoming features"

HOWEVER is the sources of the HDRP have the ddgi code, I want a pick at it, is there link?

 

The most interesting part for me is that Unity designed the raytracing API to be independent of any pipeline. Of course, there's quite an amount of work to be doing to support it but I think it makes sense for Universal to have basic quality of life features hopefully ported down from HDRP:

• GI (baked or otherwise)
• Reflections
• Shadows

The basics, that can turn even a simple Universal Lit scene into something pretty stunning, so you can target mobile and console within the same pipeline. If you know you will never go lower than HDRP then you can stay on HDRP and push quality even higher.

But I strongly believe that with Raytracing support in Universal pipeline, adoption rates from Builtin will soar, which reduces how much money Unity spends on keeping builtin around. Give it enough time and it'll cover the cost of supporting Raytracing in URP, probably. Somehow. Hopefully.

Anyway get on with it Unity. Make some magic already.

 

• Decals.

 

And after URP gets as bloated as the old built-in pipeline, I suggest Unity start a new one that is actually fast. Lightweight Pipeline has a nice ring to it if they're looking for name ideas.

 

Can you be more constructive ? Noticed a bitter trend to your posting. You alright?

 

EDIT: Maybe never mind all that.

I wasn't very well, I'm better now. Thanks for asking.

 

Well I was just concerned. I mean you're a regular but if you're going to be angry, the unity forums can't solve that problem.

 

Back to the original question of when the URP might support raytracing, I suspect the answer to that is there are no plans to support raytracing in the URP. Raytracing is still bleeding edge tech, and the URP is meant more for universal portability rather than bleeding edge graphics tech. The HDRP on the other hand is where you’ll find all the new bells and whistles.

So really this is a situation where most raytracing uses requires really high end hardware to be of real practical use for things like GI, or reflections. Shadows might come sooner, but as seen in games like World of Tanks and Modern Warfare, current implementations come with significant limitations.

 

Yeah. I do see the merit in investigating this stuff one day, but now isnt the time. Especially since plenty of people are still waiting for what they consider to be unacceptable limitations of core URP lighting etc to be overcome.

 

That's the thing, I'm not sure it's worth overcoming the limitations to reach what Builtin was. That's old thinking.

A 200 dollar card offers more than acceptable RTX performance now, and in a year, I can't see any non raytrace GPUs being released outside of mobile or embedded.

It seems like I'm way too early here, but the rate of change is you start now and in 2 years time you have something ready for market. Unlike how things have been so far.

LWRP was suitable for the slow stuff, Universal aims to be what? LWRP with more lights and some post effects? I don't see Universal being useful unless it solves what people are really asking for:

Something that can do fast mobile stuff... yet when they port, they want a one button solution that brings out all the sparkles for PS5, next xbox, high end rigs.

I don't see this being too soon even slightly. I see it as being quite late actually. Even porting the (raytrace) code from HDRP and tarting up would take a couple of years - long since past next gen console releases.

Really I just want Unity talking about this seriously. They made the API SRP neutral for a reason. Customers have asked to do the high end from the low end painlessly since SRP was introduced. Don't give them something from 2 years ago in 2 years time. Give them raytracing in 2 years time.

 

Disagree. Dont want to argue about it though, will wait and see on that one.

Again I wait to see what Unity are actually going to do with this thing. So far all I really know is that there is an adoption problem and they decided to rebrand LWRP because they decided part of the adoption problem was down to a perception problem. And they are nowhere close to adding enough actual features to Universal to meaningfully shift perceptions.

Its clear plenty of people want this and this is one of the things that also causes perception problems and lower than desired adoption. Its a fairly complex subject though, I dont think RTX/DXR etc are a magic fix for this. I do quite agree that they could be part of the solution one day, but I think the core of Universal needs a bunch of stuff doing to it on a more general level first, including some stuff that would need to be there to get the most out of DXR anyway.

I do not agree with this estimate, it could be done much quicker than that if the pipeline is in a suitable state to receive it. But of course 'tarting up' is an open ended part of the mission that could take 5 days or 5 years depending on the details of what you had in mind.

Theres a lot I could say about a broader version of this topic, that I mostly wont because I've said it before. But I will say there is a bunch of other critical stuff that they should have been talking about beyond the initial announcements too, eg the whole GI situation. I dont think raytracing related announcements based on harfware like RTX on APIs like DX12 are the most pressing thing that people are demanding to know the future of, its much lower down the list and although it can be part of the solution in some areas it is not broad enough to fill all the essential gaps in the medium term.

Given where raytracing is now, from hardware to graphics APIs to how far Unity have got with HDRP implementation, I think they are targeting the right areas first and are doing things on this front in the right order. I'd give that some time to mature and see which parts of it get used in games by people beyond the niche subset of high-end uses/markets (eg non-gaming) that have the luxury of using all that DXR has to offer.

As for reasons why they make the API SRP neutral, dont forget that when they first started going on about SRP's, they put a lot of emphasis on people making their own pipelines or completely modifying the ones Unity develop. So they still have to cater to that too, even though such aspects arent what most users who post on forums are into at all, they need Unity to do all the heavy lifting.

 

It depends on what you mean by “acceptable performance”. A GeForce RTX 2080 Super can’t run most RTX enabled games at 1440p 60hz, some titles it struggles hitting 30hz consistently. That’s a $750 GPU. The much more expensive 2080 ti and RTX Titan don’t fair much better there either. The $200 1660 Super won’t even get consistent >20hz frame rates running those titles at 1080p with any raytracing features on. Almost every title that uses raytracing also uses some form of TAA or computationally expensive denoising to hide the noise current implementations have due to the low ray counts even the top end hardware is limited to, and URP currently has no plans to support TAA.

I should note for the RTX cards I don’t count the semi-bogus DLSS benchmarks, since that’s often rendering the games at 900p or 720p (or lower!) and using temporal upsampling to hide the actual render resolution. I’m talking about actually rendering at 1440p.

Basically the only raytracing something like the 1660 can handle is some shadowing, and even then it’ll be limited to the same problems other real-time raytraced shadows have, like having no support for vertex shader deformation, and skinned meshes having a significantly higher cost to cast shadows from.

 

Yeah I must admit I am curious about hippocoders experience with RTX so far that has made them so optimistic about what its the best solution for, performance, timescales etc.

I have just revisited the 'How the Lightweight Render Pipeline is evolving blog post'. Here are 3 statements from it which I think are actually reasonably compatible with what hippocoder and myself have been saying, even though we are not on the very same page over these issues. To start with, it can remind us of what timescales Unity have already suggested:

https://blogs.unity3d.com/2019/09/20/how-the-lightweight-render-pipeline-is-evolving/

So yeah, if you are lucky then the agenda scheduled for 2021 is where your Universal raytracing dreams could begin to turn into something, which might be more likely if stuff popularised by RTX/DXR has made it to other cards/graphics APIs has also flourished by then. I still wouldnt bet on it though, depending on performance constraints and what non-raytraced higher-end aspects of URP have improved.

Anyway bottom line for me is that I actually like the 2 pipeline separation, but I can totally see why developers being forced to make a choice between one or the other is often not the sort of choice and flexibility they were clamouring for. There are several possible different reasons for this, such as:

a) But the right choice for me is both pipelines and there isnt much tooliing/conversion to help with this - pain point!
b) I am not confident making the correct choice because there is a lot of stuff I need to read and learn first, including stuff that is still half-baked or has changed during the evolution of the pipelines.
c) I'm chasing moving targets with unclear roadmaps, sample projects of different sorts that end up only working with certain editor and pipeline versions. Unity are getting a bit better at eating your own dogfood but not over a sustained period of different engine versions and pipeline evolution.
d) I like choice, but not when I feel trapped by the choice and unable to easily change mind.

Some of these will naturally become less of an issue if things settle down and mature nicely. Others will have to be pro-actively tackled. Universal and the stated motives for it acknowledges a bunch of that, but many of the things it aspires to are not things I expect to get to try myself or hear technical discussions about for a long time to come. And just because URP is going to cover much more territory in future, doesnt mean the more exotic stuff will exist anywhere but HDRP. If the technique doesnt scale down usefully, I dont think it will belong in URP. If aspects of raytracing trickle down into the low-medium end successfully in the years ahead, it makes more sense.

if I were going to be targeting next-gen consoles in their early days, choice of pipeline I would make now still depends on the sort of graphics my game needs. If I wanted to make something that 'looks like next gen eye candy' the I dont think there is anything Unity could possibly tell me today that would make me choose anything other than HDRP now. And that would change till I saw the results of their 2021 plan for URP, so any project of that sort I start for next gen consoles in the next 18 months is highly likely to be HDRP based.

 

As long as they roll back a GI solution that does what enlighten did yesterday (ye old time).

 

Have a look at unreal engine people... Years ahead!.. Raytracing is mainstream and unity is only experimental HDRP only??? What about support for Standard Pipeline? How about DLSS 2.0?

 

I really doubt standard pipeline will ever get new features development now with the SRPs being "stable" (right...) and URP probably being in line to replace standard completely in the future years. IIRC the core raytracing graphics API is available regardless of pipeline so if someone needs it and has the knowledge they can always do their own implementation.

With other points I 100% agree.

 

If Unity can figure out a way to make this possible, it would be great; but I don't necessarily expect it. I don't know of any other renderer that achieves support for super low-end hardware while still fully exploiting the latest GPU tech, so I'm seeing that option as "maybe not realistic" for now. If you look at UE for example; they simply made the decision to not support low-end mobile very well, and that's what allows them to push their tech. UE pretty much only has an "HDRP"

I also feel like that would go against the URP's mission statement of being the simple & easily maintainable render pipeline whose rendering features work everywhere, while the HDRP is the render pipeline that is unconstrained by those limitations. I sincerely think that this strategy of two pipelines is a good idea. Remember before the SRPs were a thing? One of the main sources of complaints against Unity was that people hated how the engine had to be limited by the common-denominator hardware it had to support. The engine had absolutely no hope of offering a competitive AAA rendering solution with these limitations. Multiple RPs were one solution to that, and the other would've been simply dropping support for low-end hardware, which is surely not in Unity's best interest

But the issue I see is that the HDRP is still really not there yet, and it's too difficult to trust at this point. Many people are seeing performance & stability issues with HDRP.... so projects that should be using the HDRP in theory end up using the URP instead. The ideal scenario -aside from the magical pipeline that does everything- is if the HDRP becomes a super reliable & super robust renderer that works well on anything from high-end mobile to PC (meaning it'd be an equivalent of UE), and low-end mobile support can be achieved by switching the pipeline to a URP pipeline asset in the same project

 

Hi @Unity! Wanted to ask if there are any news around this... it'd be so great to be able to add raytracing to a URP project! Even if it's shadows/reflections only.

 

I don't really think RT and URP goes well together. The two stand very opposite ends of the spectrum...

 

I don't see issue on having RT on URP. URP isn't meant to be the lightweight renderer anymore, it's meant to be universal renderer for all Unity supported devices. Having option to add RT effects to URP would be awesome IMO but it's pretty clear it's not planned at all.

 

Recently vulkan announced support for raytracing, will that affect this somehow?

 

I think URP needs to be comparable to builtin before they should even consider fancy additions, in both terms of features and optimizations, both of which are lacking at the moment. Obviously at some point raytracing will become so normalized that they will add it, but URP doesn't even support point light shadows or light cookies yet :') there's a long way to go

 

Isn't this a mute point with the SRPs being moved back into core Unity. With both HDRP and URP living in the same project and shader graph allows you to develop with both render pipelines at the same time?

This is currently what we have been testing in Unity 2021.1, i.e based on current pipeline the correct assets are loaded and our software sets settings for the current srp.

 

It would be very helpful if Unity can provide intersector and shadow ray (and possibly also denoiser + bluenoise sampling) API that is compatible with Metal and Vulkan. I never played with Vulkan directly, but Metal ray tracing is really easy (and super performant) to work with. And the workflow/API is probably as straightforward as it can get.

My current compute-shader-based path tracer has all the bells and whistles, works on desktops and ipads, and is about 2-4x faster than optimized burst + jobs version. But a native metal implementation still trumps in performance.

So it would be extremely nice if Unity can step in and let me just code my path/ray tracer with one set of API and be able to deploy on all platforms with the best performance possible.

Just want to add that burst + jobs is awesome. It's probably the best thing that Unity pushed out in recent years. CPU-bound problems are no longer problems in Unity.

 

Isn't the point of URP to be lightweight and to be able to run on any device?
HDRP is also using the SRP, but is made for high end devices to push high fidelity games. I don't see why they would add ray tracing in URP before fixing/adding other things or before it it working with great performance in HDRP

 

Pretty sure it's main goal nowadays is to be "Universal" and not just lightweight, which is why they changed the name too. Universal would mean it covers all bases, they just added deferred path to URP and now forward+. It would make sense for Unity to add also other high end features to it since HDRP isn't universal at all, it only runs on few platforms well and even on Windows it barely scales down (in comparison to how URP/built-in RP runs on the same computer), which limits your userbase a lot.

If Unity ever gets the cross-SRP work fully done and we could just toggle between URP and HDRP, that would be a totally different thing but even with their recent work on the topic, it seems like they still keep building many foundational things separately and some things will inevitably remain only a thing for URP or HDRP.

 

Forward+ has been added? O_O Where is this info?

 

It was merged about month ago: https://github.com/Unity-Technologies/Graphics/pull/4500

Since it's been merged this long time ago, I'd expect it to be on recent 2021.2 alphas URP already but haven't checked it myself.

 

There is no mention of forward+ on any of the 2021.2a changelogs

 

It's still WIP according to this: https://portal.productboard.com/uni...visual-effects/c/261-forward-renderer-support

 

Can someone tell me if HDRP also uses Forward+ or Forward rendering?

 

HDRP uses tiled deferred, frustum clustered deferred, or frustum clustered forward (aka a form of forward+) depending on what's being rendered and what settings you use. Might also use tiled forward ("classic" forward+) in some cases, but I'm not sure.

 

Just shiming in on this one; we're using HDRP 10 in production and it's super reliable. We would not even consider jumping back to built-in or URP and we're developing on PC, Mac, PS4, PS5, Xbox One and Series S/X.

High end mobile should work as my build on Apple Silicon (ARM) looks stunning and runs steadily at 1080p on the M1 with decent quality settings. I wouldn't be suprised if I could have a build running on the latest iPhone as well.

The last thing I want is Unity investing their time and resources on URP high end features when that's the role of HDRP. I believe this is why they are not planning on supporting raytracing to URP. Anyone wanting that simply should use HDRP, end of the line.

 

This would be fine if HDRP actually scaled down well.

And therefore limiting the userbase on Windows because HDRP forces you to put way higher min spec for the game. IMHO we shouldn't have to pick between high end visuals/features and scalability.

 

Well the fact that I can have a complex 3D game with SSR, Subsurface Scattering, Translucency, GPU particles and a lot of lights running on a GTX 1050 at 30+ FPS @ 1080p tells me that HDRP scales down well. Of course URP allows you to reach a wider audience, but it looks like total crap unless you stylize your visuals or don't need physically accurate rendering.

 

What's preventing SRP from being a concrete, indefinitely scalable (up and down) implementation, where you configure stuff with real units and your shaders interpret them as what they are for realistic results or bend their interpretation to achieve a friendlier workflow? What's so fundamentally different between URP and HDRP? HDRP tanks performance by simply being enabled — on an empty project. What's that about? Even URP (both 2D and 3D) is a lot slower than built-in at the beginning — it just scales up better.

We don't have a "Scriptable Sound Pipeline" specialized into "Acme's Discount Sound Pipeline" (with "loudness") and "Sony's Hyper-Mega-Power-Realistic Sound Pipeline" (with decibels). Why do we need that for graphics?

 

HDRP and URP are entirely different beasts, built by different teams. Both have strengths and weaknesses. I also wish that they had build a single pipeline, instead of making duplicate work (ie features on one **eventually** being implemented on another, such as deferred rendering, forward+, cached shadows, etc). But the reality is that they are indeed different and cannot be merged, and neither one is going to be dropped any time soon. :/

 

Is there any specific reason URP won't have raytracing? Even from an artist point of view it's much easier to design a scene without having to build lightmaps all the time.

It's getting increasingly frustrating having to pick between pipelines. I want raytracing to not have to worry about lightmaps during production and to increase graphic fidelity but the less realistic lighting of URP.

 

URP first needs to reach feature parity with the built-in RP. Namely motion vector support, which is required for motion blur and TAA, and I believe raytracing as well. So, given the track record, it may be 2-3 years, before raytracing is even considered.

I haven't touched HDRP, because it has far more bells and whistle I'd make use of. I'd definitely want to see raytracing support, particularly for reflections, shadows and GI. Not even to target photorealism, just for natural lighting. But if URP isn't getting raytracing at all, it's practically already on its way out for the mid-range.

In hindsight, I wonder if Unity would have gone with a single SRP, scalable from potato to next-gen.

 

Movec support already landed on github:
https://github.com/Unity-Technologies/Graphics/pull/4408

There's been additional tweaks to this after that PR too. It's marked as released on 2021.2 alphas on productboard:
https://portal.productboard.com/unity/1-unity-platform-rendering-visual-effects/c/218-motion-vectors

 

Absolutely spot on in the spirit of the thread. The whole point here is that we can't have a Universal pipeline without it. Universal is supposed to go from low end to high end.

I want my game running on switch and on PS5, with the PS5 one having great shadows/GI/reflections. We all know that's possible and there are more stylised games than ever using RT today. Not least minecraft.

So please Unity, do the right thing. Let us scale without pain and don't force us to maintain two pipelines on one project with dodgy buggy switching that will take longer to resolve than including RT support.

 

While I wholeheartedly agree with hippo's previous reply, I think It's important to recognize that RT is fundamentally more resource demanding than rasterization no matter how technology advances in the foreseeable future.

That said. I also think there may be a path to get there (RT on URP). First HDRP's RT needs to get out of experimental status and support more platforms that don't use nvidia cards. Namely, Apple's Metal ray tracing needs to be supported. (It's a big can of worms and I don't know if anything on that front is being done right now)

A major purpose of URP is to target a wide range of platforms and devices. From Unity's perspective, I cannot see how RT on URP can happen without supporting Apple devices.

 

I think it would be perfectly fine to have some high end features for URP that don't work everywhere, assuming they can gracefully fall back to something faster on other platforms.

I see it as easily being able to easily add some bells and whistles when you release your game on platforms that are more powerful than what you primarily designed it for.

 

For what it's worth, this raytracing asset for built-in RP is about to get URP support now: https://forum.unity.com/threads/rel...eferred-rtx-reflections.1049696/#post-7439618

 

I think at this stage Unity should just ditch URP, and focus on making HDRP scale down to low end hardware. Or maybe have the legacy pipeline as the low end option (then phase it out in two years when low end will equal current day high end). This way there will only be one pipeline with no fragmentation. Unreal Engine 5 does that successfully.

Having one modular pipeline that scales down to low end devices with optional support for high end features like raytracing and more complex shader model is the way to go, otherwise Unity is shooting themselves in the foot. It’s technically possible because competitors already do it.