URP lit shader will not receive shadows while transparency is enabled

I've noticed that the LWRP/URP lit shader (or any other URP shader) will not receive shadows while the transparency is enabled. Is there a workaround for this? Or maybe some kind of shadow catcher material? Maybe I should go back to the default RP and try its mobile shaders.

 

Thanks for the information.

 

Hi, got URP 7.1.8 released 22.January. Where can i find the toggle that is mentioned in the github comments?

 

@ElvarOrnUnnthorsson Do you have a link to the ticket for this issue?
I'm working on a project that will need shadows on a transparent surfaces using the URP.

Sorry, I just noticed your link in your previous post.

 

@Elvar_Orn I'm now with URP 7.2.1. Do shadows still not work on Lit shader with Surface Type: Transparency? I have "Receive Shadows" checked.

@GVUnity were you able to see shadows?

 

Having the same issue as above with 2019.3.4f1 & URP 7.2.1, no shadows on lit transparent shaded objects.

Simple scene with a stack of objects in Y

spot light shining down Y at the top
cube
transparent plane
opaque plane at the bottom

Shadow on the opaque bottom plane of the cube, but nothing on the transparent plane at all.

In answer to the questions below

In the frame debugger, yes I do see a pass rendering to a shadow map, can see the shadow on the opaque plane at the bottom of the stack but nothing on the transparent plane

I do have "transparents receive shadows" turned on, on the material

My spot light is set to realtime

Light does not seem to have a "cast shadows" option, however given I am seeing my soft shadows on the bottom opaque plane, Im going to assume this is correctly setup.

Similarly cant see a "realtime shadows" option in the pipeline asset, there are options for "Cast Shadows" which are turned on, and again I am seeing shadows on the opaque plane.

Am I missing something silly?

 

2019.3.7f1 URP 7.3.1 still not working properly.

 

I am using URP 7.2.1 and, you guessed it, for me the "Transparent Receive Shadows" is also not working

... for the STANDARD URP materials. However, I noticed that my shader graph material works just fine. Threw that sunofa on my other objects and sure enough my transparent objects had shadows.

It is, of course, annoying and unintuitive to recreate (and test!) a couple of different shaders, but I hope this at least helps anyone who finds this thread.

UPDATE:
In fact, here is a recreation of the Simple Lit shader to get you started.

 

Is this issue still going on ? I cannot use URP at all if this simple base feature is not working

 

Hi, thanks for the response.

Is there a way to get an insight of what the fix was ? I have a shader based on URP Lit one, i started it on LWRP 6.9.0, and did some changes as moved to URP. Now i am not sure if is the fault of my shader based on older LWRP or new URP issue. Turning from transparent to AlphaTest works for shadow receive.

Also is there any news about the slowdowns in Unity editor after Unity 2019.3.1f1, i have sent this bug long time ago and there is no news, this is also crucial for my asset and currently is not working at all after Unity 2019.3.1.

https://fogbugz.unity3d.com/default.asp?1233944_744uepe09a7cbra7

Thanks in advance

 

Thanks a lot, i will try that.

 

We updated our project from LWRP to URP and are seeing similar issues. Any chance switching between the two could cause the problem? It's happening with shader graph shaders, as well as built-in Universal shaders like unlit particles. Toggling transparents receive shadows has no effect.

 

Hi, not sure if it's the same issue, but the terrain does not receive shadow at all while using the default terrain shader (URP/Terrain/Lit). The shadow works fine if I switch the shader to hidden shader Hidden/Universal_TerrainVisualization, which I came across trying different shaders.

The problem is that I can't add layers on the Hidden/Universal_TerrainVisualization. I tried manually updating the default shader to mimic the hidden shader without success.

Any advice how to make the default TerrainLit shader receiving shadow?

 

Any luck solving the problem? I still have no shadows casting from transparent objects, they get painted as soon as I switch the material to opaque.

 

In URP 7.3.1 when using Lit shader and transparent mode doesn't seems to cast shadow. I don't understand how hard can it be to fix this issue.. This thread is almost 1 YEAR old..

 

A hack to solve it, is just to add a second version of the object with a material set to opaque but with alpha cut out and in the renderer mark it as render only shadows. They should use alpha cut out by default for the shadows or something.

 

I can try and find out @UserNobody, I'll ask around for you!

 

Hi Shaun, can you please follow up with this one? This is a long standing issue and if the goal really is to close the feature gap between URP and the Standard Renderer then this is a particularly glaring omission to be left hanging.

Definitely a pain point for me.

 

@Shaunyowns Any news on this issue?
This is a really important and basic feature to a lot of people, including me.
I hope this gets fixed soon.
Please keep us up to date.

 

Sometimes I wonder if Unity pays any attention to these posts, and just fixes or updates things at their own leisure!! It really does not seem like they do pay much attention!!

 

Hey @Matt-Cranktrain, @Lyxodius

I'll ask around again and see if I can get a response, apologies for the delay!

 

@Shaunyowns
Hi!

Any news on this situation? I'm facing the same problem. I want to use 2d plane / sprite as surface for texture that contains alpha channel information. When using URP / Lit -shader on a plane it casts shadows but once I activate alpha (change surface type to Transperent) I loose casted shadows.

 

Maybe not quite directly related, but - is it possible to create matte/"shadow-drawer" effect using the URP?

In fact it means fully transparent plane, but displaying shadows casted by other objects (see attached example picture).
For the original Unity 5 renderpipeline the effect was possible via this Unity's Keigiro Takahashi shader.

Based on discussion above, receiving shadows on (semi)transparent surfaces does not seem to be supported...

 

First go here and open that.

Then Edit this to true

 

Now next on my list is how to fix this darkening
Standard RP

URP

 

Looks like there is no GI or Ambient color (sky).

 

There is, but is way way darker.

 

Can you show all settings, materials and lighting window?

 

It has nothing to do with that, is a simple scene with default settings. It works with the standard shaders, but when you switch to URP in unity 2019.4 the shadows and ambient in general is darker. Is a shader problem not a wrong setting.

 

So what's the answer?

I love it how even you yourself being within Unity can't get any response from others in Unity, for 3 months and at least 2 attempts! And how it's the same sheetuation as when you tried to ask them about the deferred renderer (https://forum.unity.com/threads/urp-deferred.931872/#post-6345231)

That makes us something like brothers here <3

I have no idea what's your company's communications model is, but it looks like Unity is unaware that it's possible to actually talk with people, both inside the company and outside (because why, right?). Not much of any unity there is in Unity. A better name would be Obscurity. "Obscurity Engine" -- I like it, pretty much describes the feelings from working with it and from trying to get any support.

 

Well every worker at unity is like that, I have not seen any help given to anyone ever since I joined this forum from one of them, only good people who use unity helped with a mod of a shader or a fix in some areas.

 

I just created a new lit shader graph, applied it to an object and it's not receiving shadows. If I apply the built-in URP/Lit, it does.

Unity 2020.2.0b14.3668
URP 10.2.2
Shader Graph 10.2.2

 

I found a shader on URP with an object receive shadow while still transparent. You can also adjust the transparency level.

 

Hi, this is still an issue, i'm using Unity 2020.2.4f1.

Changing the Surface Type to Opaque makes the whole plane object cast a shadow, but Transparent does not cast any shadow, can Unity devs please fix this problem?

 

Bug still exist in 2020.2

 

We had this issue for leaves but we changed the material to opaque then activated alpha clipping and chnage the values. Hope this helps someone

 

thanks for this bro!

 

urp v12, still no shadows when a lit shader enables tranparency

 

Will this be ever added? cast shadows on transparent pbr's in urp?

 

For anyone finding this because their leaves on trees are NOT casting a shadow with basic URP Lit shader.

• Switch the material back to Opaque and then check 'Alpha Clipping' instead

Not sure if this works for other transparent needs, or any drawbacks? I'm a beginner

 

Yes, this has already been stated in this thread (many times actually, I think people post before reading). Setting it to opaque also helps with the Z-fighting. But it's not a real solution, just a hack, since it doesn't allow for semi-transparency. You can't have values ike 0.5 alpha, only 1 or 0. I proposed above that you can use the cutout just for the shadow, if needed. Check it out. Still, a semitransparent shadow should be available out of the box.

 

Any update on this from the Unity team? As posted in this thread, people are modifying one line of code in the URP package or are having to create a duplicate mesh (ugh) set to "Shadows Only".

 

Still fighting with this on the latest beta build (2022.1.0b3.2528), and every time I try to modify the URP package it gets reverted

Creating my own shader graph that casts and receives shadows the result casts shadows but is visually wrong when compared to the opaque surface type
Transparent:

Opaque:

 

This is a sorting problem within a single transparent mesh. It’s a classic problem in real-time 3d rendering, and it’s basically unsolvable. You can mitigate it or revise the assets.

 

For anyone still having problems with the lit shader not casting shadows when surface type is transparent, try changing the shader from Simple Lit to Complex Lit, that fixed it for me.