Considering jumping ship from HDRP to URP (LWRP). What's the difference now?

Unity Engine
,
1

I’ve been using HDRP for maybe 8 months now, having migrated from the built-in renderer back in December. I made this decision mainly to start being able to use Shader Graph and the Visual Effects Graph. However, my project is being build for Desktop + PS4 + XBox1, not for mobile or other platforms. So at the time, I chose HDRP believing it was the best choice for those platforms.

However, it now seems that URP is really catching up in terms of visuals. From the 2019.3 beta blog post (Unity Blog), it seems like URP will soon support all of the post processing effects I’m using in my game.

I’m not really pushing the envelope in terms of graphics, as I’m a solo-dev here generally building everything myself from scratch. You can get a good sense of my look and feel here:

Video

https://www.youtube.com/watch?v=YBwXaK0Ry-4

I’m going for realistic, but certainly not next-gen quality. My biggest concern is whether the game will run well for the most possible people, and it seems that HDRP’s requirements limit the audience somewhat.

So I’m debating whether it will make sense for me to switch from HDRP to URP in the near future. But I was hoping to quantify the impact of this decision. I was hoping some people might have answers to some of the following, as it’s not easy for me to determine this from the existing docs.

  1. Are system requirements for URP lower than HDRP?

HDRP requires Shader Model 5.0 graphics card. Is this also the case with URP? In short, would using URP allow more people to play my game?

  1. Should I expect better performance from URP than HDRP in general?

Assuming I’m not pushing HDRP to its limits, would you expect a given scene of similar quality to run faster in URP than HDRP?

  1. What major features will I be missing out on with URP compared to HDRP?

It seems that Volumetric Lighting is only in HDRP, not in URP. Are there any other big features I won’t be getting in URP? I don’t plan on using raytracing, so no worries there, but I rely heavily on Realtime GI.

  1. In short, what’s the big difference between HDRP and URP these days? Why would you go with HDRP compared to URP?

  2. Any horror stories migrating from HDRP to URP? I know HDRP uses a MaskMap instead of individual textures, which will mean a lot of migration changes. Any other major hiccups migrating from HDRP to URP?

Thanks.

6 Likes
2

There are tons of limitations with LWRP to consider:

  • Maximum of 8 pixel lights EDIT: Apparently this is no longer true.
  • No pre-computed dynamic global illumation (this has big influence on visuals)
  • Reflection probes are sorted per objects and don’t support blending
  • Not sure on this one, but I think only the directional light can emit dynamic shadows
  • No Motion Blur, no SSR, no Ambient Occlusion
  • No volumetric fog
  • No subsurface scattering
  • No realtime area light
  • No high-LUX HDR support
  • No iridescence
  • No double-sided transparent render (this maybe be done via Shader Graph)
  • No built-in decals (this may be hand coded in LWRP)

…and much more.

The main advantages of LWRP is that it is fast and currently super stable. It is also closer to what we’re used to in term of content creation inside Unity.

Still, in a realistic context, I’d certainly work with HDRP since there are features that I cannot live without, such as Dynamic GI, AO and volumetric fog.

EDIT: Of course some of these features can be hand coded into LWRP, but I don’t think that this is the point here. Out of the box, HDRP is much more cutting edge in term of visual accuracy than LWRP, and that is why both pipelines exist.

2 Likes
3

Are you aware that Enlighten support is being removed from HDRP?

https://discussions.unity.com/t/747803

1 Like
4

Of course, in 2023 for already-supported platforms, and replaced by something else in 2021.

2 Likes
5

Not sure where you are getting 2023 from? 2019 LTS and not touching 2020 versions of HDRP?

1 Like
6

Thanks for breaking it down like that. I didn’t even notice that Realtime GI wasn’t supported in URP, which is definitely a dealbreaker. Thanks for pointing that out. HDRP it is.

It would be nice if Unity would author a comparison table for URP and HDRP, kind of like one of those tables that shows you what features are supported in each higher tier of a product, so that users could quickly view the differences between them. Basically one of these tables, but for HDRP and URP features: https://store.unity.com/compare-plans

2 Likes
7

All fairly wrong now, check latest blog for Universal, you get mot of the post effects, almost no light limits and the rest is available via shader graph… so Universal is a big deal now, and a big improvement and a candidate for actually replacing ye olde built-in.

https://blogs.unity3d.com/2019/08/27/unity-2019-3-beta-is-now-available/

edit: I know technically it’s right but it won’t be going forward.

5 Likes
8

Try to fact check first :stuck_out_tongue:

9

Which ones were wrong? Most on the list were somewhat accurate (altho I wouldn’t promote enlighten support when it’s not been great on HDRP and it’s getting removed from the 2020+ releases), I see they added motion blur now (do they finally have motion vectors in URP?).

1 Like
10

I said “fairly wrong” in context of original poster not having seen Universal and not seeing how far it’s come. You can approximate pretty much everything now via the graph in Universal… The light limit on screen is way better too.

1 Like
11

From that list, these are all correct

I would assume once the deferred render is added to URP it will get some of the more advanced Post Processing effects that uses compute shaders - https://github.com/Unity-Technologies/ScriptableRenderPipeline/commits/universal/deferred

1 Like
12

Yeah, I was mainly comparing the featured listed in that blog post, and found that it nearly covered everything I was already using in HDRP, and figured maybe URP would be sufficient. I merely assumed Realtime GI was supported in URP, because I figured it was simply part of Unity (as it’s in the built-in renderer). I probably would not have made this post at all if I’d realized beforehand that URP didn’t support Realtime GI.

It makes me wonder now, though, whether Realtime GI is possibly coming to LWRP. There’s this post ( https://discussions.unity.com/t/728286/2 ) from January stating that it’s planned. So maybe some day.

Mainly my concern was whether I could have a wider end-user base for my game if I switched to URP, and whether a similar scene in URP would tend to run at a higher framerate than under HDRP. I’m having second thoughts now about whether my game really needs the bells and whistles of HDRP, given how far URP has come. But I guess until/unless Dyanmic Realtime GI support is added, that question will remain moot.

Anyway, thanks everyone for all the feedback and help so far.

13

Keep in mind that since then, they announced the deprecation of Enlighten.

Enlighten deprecation and replacement solution

So I think its more likely they will focus any URP realtime GI efforts on their new replacement GI system that will be under development in the year+ ahead.

I do think it is easy to speak of GI too generally and miss all sorts of detail though. I’m no expert, but I note that there are quite a lot of different GI sections and capabilities listed in the built in renderer-URP comparison matrix:

https://docs.unity3d.com/Packages/com.unity.render-pipelines.universal@7.0/manual/universalrp-builtin-feature-comparison.html

1 Like
14

Thanks. Seems I also completely missed the upcoming deprecation of Enlighten. I’m reading through that thread now. I haven’t yet determined conclusively from that thread whether a realtime GI solution will be in place for 2020.1, when Enlighten is removed from HDRP. Hopefully so… I’ll be keeping an eye on that. Thanks for the heads up.

15

They are all fairly right, actually.

The 8-lights limit is the only one that is no longer true and thanks for pointing that out.

To the “Considering jumping ship from HDRP to URP (LWRP). What’s the difference now?”, the answer is that a lot of features are HDRP-exclusive. The average user cannot code SSR or decals into the universal pipeline. The same is true for realtime area lights, iridescence, subsurface scattering, volumetric fog and so on.

…another thing is realtime raytracing, which is currently only available with HDRP.

The bottom line is that if you are making a realistic game, and that visual accuracy is a big part of it, HDRP is a better option than the Universal Pipeline.

2 Likes
16

That’s really the tough question to answer, for me anyway. The visual style of my game is realistic, but not hyper-realistic or photo-realistic. This is mainly due to the limitations of my expertise in modelling, and my lack of an artistic style. It’s hard for me to judge whether the relatively simplicity of my visuals really necessitates the power of HDRP, or whether it would mostly look the same using URP. That’s obviously not a question anyone but me can really answer, and it comes down to what kinds of effects I want to include.

I think it turns out my main concern is moot. This Steam Hardware survey page (https://store.steampowered.com/hwsurvey/videocard/) says that about 94% of users have a DX 11 or higher, which tells me that up to 94% of users can run HDRP games. (Maybe not at great framerates, but it’s possible.) So that’s probably comfort enough for me. I’ll stay on HDRP for now, and not worry too much about the stragglers with DX 10 and under who won’t be able to play my game.

Thanks again for all the information and help in this thread.

1 Like
17

Just the fact that Unity samples (ex) run beautifully on PS4 is a good pointer that it is being developed with scaling to lower end hardware in mind. Our game comes out in a couple of years, and PS4 hardware at this point will be comparable to the median laptop.

But I have to say that HDRP is quite harder to develop on than built in or URP. There are some extra steps in the making of all assets and scenes compositions. As it is our second game and that we have decent funding, it is acceptable, but it is something to think about.

If that is true then I’d start with URP, if I were you.

18

Maybe. Certain features of HDRP need the right art assets to get the most out of, but others dont. Depending on the desired style, there could still be some HDRP lighting system, post-processing effect, volumetric fog, or shader feature that really makes a good difference.

1 Like
19

what is this URP post effect?? atmospheric scattering? volumetric? i can’t see this fx on URP postpro effects? [2019.3 URP] how to do that?

thanks.

4913723--475796--Capture.JPG

5 Likes
20

As this was a central part of this discussion - please note that the “light limit per object” hasn’t increased at all. It’s still 4 (and supposed to go to 8 for non-mobile targets). Only the “light limit per scene” has increased, which is only relevant in giant scenes where at most 4 lights shine on the same thing at the same time.