Hi everyone, I just wanted to share my experience so far regarding HDRP since its release. I’ve been using HDRP as a base platform to build graphical assets for my next project that would be using HDRP in the future.
I’ve used HDRP for about 3 weeks and figured I’d try to share my thoughts on it. I hope this post can share a bit of insight to those who have yet tried HDRP or have just fired it up but not spending a lot of time with it. I also hope that the Unity HDRP devs can benefit from this in any way they can.
At the time of this writing, I am basing this post on Unity 2018.2.0b7 and 1.1.1.10 preview version of HDRP. I will be referring to the current Unity as “Legacy” and HD render pipeline, “HDRP”
Point 1) It is almost ready for production - sort of.
Despite what Unity Devs say, I think it is relatively ready for production. It has many things constantly changing and breaking, but in general, publically released versions available via the Package Manager is good enough. I can feel the rapid improvement of HDRP week after week, and so far I’ve found that it is actually on par with the Legacy Unity in terms of stability. The number of patches released after its launch is quite astonishing. Given that HDRP is handling the graphical side of things mostly, starting on a full-blown project seems like a viable option. It will be a bumpy road, but every project is, and I am willing to bet that HDRP will pay off in the long run given a 2-year project versus working on a next-gen graphics project on the Legacy with Asset Store shaders and FX slapped on.
Point 2) It is definitely a huge upgrade to graphics.
SSS works well and is quite performant. Post-processing seems better (I found TAA and motion blur showing better results) and the PBR seems way better, especially with low gloss materials. I also find it much easier to achieve photorealistic results compared to the Legacy Unity. It is difficult to point out why, but it feels right when I import it to HDRP and I often find myself adjusting the texture a few times compared to Legacy, where I’d adjust for days and still feel something is off.
See what I mean? The transparent backboard and the specularity on the rim always felt “off” on legacy, but with HDRP, I get results!
Point 3) Real-time shadows are not quite there.
I’ve found that the realtime shadows, in general, are not that different from the legacy Unity shadows. Personally, I appreciate the Contact Shadows, but the directional light shadows are just lacking. There are cascade settings that one can play around to control quality - especially near camera - but there is very little wiggle room in those settings that work without glitching shadows of other areas. I tried many different settings but always ended up going back to the default settings. I find the realtime directional light shadows quality to be very poor - not particularly bad compared to other engines, but given the premise that HDRP is aiming to be the HD platform, I find the lack of better shadows strange.
Point 4) Lightmapping is still generally broken and is in dire need of GPU mapping.
I’ve had issues with lightmapping from day one of Unity5. Truth be told, both Enlighten and Progressive Mapper is not production ready. It breaks, then glitches, but worst of all, it takes me 5 hours to bake a 100m x 100m scene, only to find out that there is something wrong with the configuration, or the lightmapper just acting out in general. Then another 5 hours and repeat until I flip my desk.
Obviously, lightmapping is not HDRP’s issue, but given that there is no other lightmapping/GI solution available on HDRP either, I thought I should still mention it. Whatever you do, currently on Unity, even on HDRP, you can’t achieve lightmapping at its highest potential. You just can’t for a production level scene. It is only viable for a small indoor sample scene. Anything beyond 10 x 10 is going to make your life miserable.
Unfortunately, Unity doesn’t seem to realize how bad the situation is. There was a presentation done about a year ago with the following title: Bake it til you make it.
Here is the video link
It does seem that lately, Unity is working on the GPU mapper
Here is the video link
While I am glad that they are working on this, it is almost 2 years late. It should have arrived with Unity 5 in the first place. CPU baking was never viable in the first place and HDRP a few years later is going to suffer. Unity said the GPU baker will be 10x faster, and it sounds great, but if you do the math, the 5 hour bake time will go down to 30 minutes. the 10x statistic could be higher or lower than 10 exactly, but 30 minutes is still a long time for a 100m x100m scene. I just hope that the GPU lightmapper coupled with PLM will be flexible enough for production.
Conclusion
Pros:
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Best graphics hands up and will dominate the future.
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HDRP team is rock solid and is working hard based on Github activity and release history.
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HDRP is already amazing this early.
Cons:
- Realtime shadows aren’t quite there yet.
- Lightmapping deteriorates the whole experience in general and turns a great product into a mediocre one. Mostly renders the whole graphics department of the engine useless for large projects.
I hope my review/thoughts helped other users. I only wrote this lengthy post hoping that HDRP will not lose traction over time and carry on pedalling to the metal! HDRP guys are doing great.