# Shadow not behaving as expected

**URL:** <https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213>\
**Category:** Questions\
**Created:** [December 2, 2022, 4:52pm UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213 "2022-12-02T16:52:52Z")\
**Posts on this page:** 14\
**Page:** 1

<div class="post-metadata">

**Author:** ![maxime1992](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/maxime1992/32/4922_2.png) [@maxime1992](https://forum.babylonjs.com/u/maxime1992)\
**Post date:** [December 2, 2022, 4:52pm UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/1 "2022-12-02T16:52:52Z")

</div>

Hello,

I’m trying to simulate the sun in a scene with a house model to see the how the shadow behaves.

I’ve got a funky shadow at the moment!

![weird-shadow](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/e/0/e0d4607de9f111b0f9cea51379ddf7a28d4c4d75.gif)

I don’t have an online repro as I don’t know where to upload my gltf file on a service that keeps the extension so that I’m still able to use the loader. If anyone knows of one please let me know and I may try to get a live repro.

Hopefully the pieces of code I’m about to share still help to see more clearly for someone knowing more than me 🙂

For the light, based on what I read, the `DirectionalLight` seems to be the more appropriate (?).  
Here’s what I’ve used:

```auto
this.light = new DirectionalLight(
  'sunLight',
  new Vector3(0, -1, -1),
  this.scene
);

```

The movement you see is just for debugging, I’ve added:

```auto
setInterval(() => {
  this.light.position.y -= 0.01;
}, 10);

```

For the ground I’ve got:

```auto
const ground = MeshBuilder.CreateGround(
  'ground',
  { width: 40, height: 40, subdivisions: 2 },
  this.scene
);

ground.receiveShadows = true;

```

And finally for the loading of the mesh and the shadows I’ve got:

```auto
    const mesh = await SceneLoader.ImportMeshAsync(
      undefined,
      './assets/',
      'house-v1.gltf',
      game.getScene()
    );

    const shadowGenerator = new ShadowGenerator(1024, game.getLight());

    mesh.meshes.forEach((m) => {
      shadowGenerator.addShadowCaster(m);
      m.receiveShadows = true;
    });
    shadowGenerator.useExponentialShadowMap = true;

```

I don’t have anything else fancy in the scene except the ground and the house. How is the shadow behaving as such?

Thanks for any help (and do let me know how to get my mesh somewhere so I can provide a live repro please)

---

<div class="post-metadata">

**Author:** ![Evgeni\_Popov](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/evgeni_popov/32/4432_2.png) [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)\
**Post date:** [December 2, 2022, 5:41pm UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/2 "2022-12-02T17:41:31Z")

</div>

See [this doc page](https://doc.babylonjs.com/toolsAndResources/thePlayground/externalPGAssets) for some solutions to host the files you want to reference from the Playground.

Something you can try:

- put `this.light.position = new BABYLON.Vector3(0, 8, 8);` after creating the light

By default, the position of a directional light is the negated `viewDirection` vector you pass in, so (0,1,1) in your case. It’s likely that this position is too close of the house (or even inside), and `this.light.position.y -= 0.01` will stuck it even more.

Try to use the inspector to debug your shadows. With a directional light, the “Display frustum” switch is of a great help for debugging purpose (see bottom right of the screenshot):

 ![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/3/c/3cacf773e517a30b9fc2f22839bea5a0ab75a399.png)

Also, some advices to help debugging shadows:

> **[Shadows | Babylon.js Documentation](https://doc.babylonjs.com/features/featuresDeepDive/lights/shadows)**
>
> Learn how to leverage shadows in Babylon.js

---

<div class="post-metadata">

**Author:** ![maxime1992](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/maxime1992/32/4922_2.png) [@maxime1992](https://forum.babylonjs.com/u/maxime1992)\
**Post date:** [December 3, 2022, 10:45pm UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/3 "2022-12-03T22:45:40Z")

</div>

Thank you so much for the reply, this is fantastic!

I took a look and here’s what I’ve got so far:

 ![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/2/1/218a5c43e8bfd66593fb27492cf2dd95ad7eaa45.png)

So indeed it doesn’t look like it’s going to behave correctly 🙂

I’ll keep digging a bit into that in the next week or so and try to make a minimal repro if I don’t get the expected result! 🙂 thanks again!

---

<div class="post-metadata">

**Author:** ![maxime1992](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/maxime1992/32/4922_2.png) [@maxime1992](https://forum.babylonjs.com/u/maxime1992)\
**Post date:** [December 3, 2022, 11:18pm UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/4 "2022-12-03T23:18:24Z")

</div>

Actually, I can see the shadow is now behaving correctly! 🎉

 ![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/5/3/5353820551c98610590efcefdb16f89e67eeb42e.png)

 ![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/2/8/28b8a413684348460493ad039343ab00d27a3bbb.png)

But I have no idea why my mesh is so dark.

On the previous picture when the shadow was buggy the mesh color looked better:

![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/4/c/4c4bb858c4a49b68ce796fc9408fc29273031af9.png)

We could see the shadow more easily. I’ve tried to attach a `StandardMaterial` to the list of meshes but nothing changes unless I set `material.emissiveColor = new Color3(1, 1, 1)` which makes the house all white and the shadow isn’t even on it. I’d like a reasonable color so I can distinguish the house and the shadow (especially the chimney one).

On top of that, is there any tweak I can make to the light so that it looks more “realistic” for a day time light? As in, the back face of the house shouldn’t be 100% dark, during day time I can still see the opposite side of my house compared to the sun angle. It’s not pitch dark. As I don’t have anything reflecting toward it in the scene I don’t know if it’s possible to make it look nice while still keeping an accurate shadow 🤔

---

<div class="post-metadata">

**Author:** ![Evgeni\_Popov](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/evgeni_popov/32/4432_2.png) [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)\
**Post date:** [December 4, 2022, 10:14am UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/5 "2022-12-04T10:14:43Z")

</div>

Try using `material.diffuseColor` instead.

To lit even the dark side, you can try adding an hemispherical light with a low intensity (0.2 or 0.3).

---

<div class="post-metadata">

**Author:** ![mawa](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/mawa/32/12384_2.png) [@mawa](https://forum.babylonjs.com/u/mawa)\
**Post date:** [December 4, 2022, 10:20am UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/6 "2022-12-04T10:20:37Z")

</div>

Well, first I godda say you did a very good debugging on this peculiar topic of using shadows with a directional light. It is not easy to understand at first and making a visual representation is really a smart way to get a better understanding of it.

> [@maxime1992](#):
>
> I’ve tried to attach a `StandardMaterial` to the list of meshes but nothing changes unless I set `material.emissiveColor = new Color3(1, 1, 1)` which makes the house all white and the shadow isn’t even on it.

Yes, fancy, isn’t it? 😀 What you need to understand here is that the darkness of the shadow uses the emissive. Understand the emissive color ‘emits a color’ that will superseed your shadow. By making a white emissive with a default level 1, you are emitting strong white color against the light/shadow. If you want nice dark shadows while keeping with a realistic lighting effect on your material, you should use an emissiveTexture that is slightly darker than the diffuse (base or albedo) with a dark emissiveColor. You can next play with the emissive\*.level to adjust the level of light/shadow. Usually a setting between 0.1 to 0.5 works best (though it depends on your emissiveTexture, the type of material and the desire result).

> [@maxime1992](#):
>
> I’d like a reasonable color so I can distinguish the house and the shadow (especially the chimney one).

Of course. Well, I guess your best option is to add a second light to the scene. The directional light alone will only diffuse light in the selected direction. If the light is obstructed from the other side, well… it is 😉 So, adding a ‘global type’ of light to your scene is I believe the way to go. It could be a hemi or a point light.

> [@maxime1992](#):
>
> any tweak I can make to the light so that it looks more “realistic” for a day time light?

This goes with the above. Realistic means there’s not just one light source of a certain type. So here again, adding a second and eventually a third light in your scene will help with that. One thing I often do is that I use two shadow generators and three lights. 2 lights cast shadows and one is used for the global (environment) lighting. Here you just need to understand that light only adds to light! 🤔 😉 This means that when doing this, you should use a lower level intensity on your lights (and adjust them depending on the ambience you want). Also note that for keeping with nice dark shadows, you can 1) use contact hardening shadows 2) set an intensity lower than 0 (i.e. -1) on the light that is just for shadow casting. Though in this case, you will need to compensate by setting a higher intensity on your other light(s).

---

<div class="post-metadata">

**Author:** ![maxime1992](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/maxime1992/32/4922_2.png) [@maxime1992](https://forum.babylonjs.com/u/maxime1992)\
**Post date:** [December 4, 2022, 11:12am UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/7 "2022-12-04T11:12:11Z")

</div>

@Evgeni_Popov

> [@Evgeni\_Popov](#):
>
> Try using `material.diffuseColor` instead

I tried it already. I’ve actually tried all of them to see if the following to see if there was a difference: `diffuseColor`, `specularColor`, `emissiveColor`, `ambientColor`. With `Color3(1, 1, 1)`.

Except for the `emissiveColor`, where I get it all white as explained (and no shadows), the others don’t change anything at all. And actually, as soon as I set a material, the house goes full black:

 ![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/f/8/f83ed98e2dd6798af4003b43ea4fb42555a1a008.png)

But if I don’t set the material at all, it’s dark, but not as much:

 ![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/4/6/46bd85901251c042305354839688d7f75f7b70e8.png)

---

<div class="post-metadata">

**Author:** ![Evgeni\_Popov](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/evgeni_popov/32/4432_2.png) [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)\
**Post date:** [December 4, 2022, 11:16am UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/8 "2022-12-04T11:16:09Z")

</div>

Maybe your normals are inverted? Try to display them and see if they are pointing to the right direction:

 ![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/4/6/46f7183290ff0468335c1f0996ab47a7693b041a.png)

> [@maxime1992](#):
>
> But if I don’t set the material at all, it’s dark, but not as much:

If you don’t set a material explicitely, you get a standard one automatically, with the diffuse color being a middle grey.

---

<div class="post-metadata">

**Author:** ![mawa](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/mawa/32/12384_2.png) [@mawa](https://forum.babylonjs.com/u/mawa)\
**Post date:** [December 4, 2022, 11:28am UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/9 "2022-12-04T11:28:57Z")

</div>

Could you set-up a playground so we can debug it. Without a PG, it’s hard to tell.

---

<div class="post-metadata">

**Author:** ![maxime1992](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/maxime1992/32/4922_2.png) [@maxime1992](https://forum.babylonjs.com/u/maxime1992)\
**Post date:** [December 4, 2022, 11:29am UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/10 "2022-12-04T11:29:34Z")

</div>

@Evgeni_Popov I think the normals are ok:

 ![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/6/9/692d5dd214ce181cfe6a70df53eec141bf880401.png)

> If you don’t set a material explicitely, you get a standard one automatically, with the diffuse color being a middle grey

yes, I was just trying to say that basically I’ve tried all the possibilities. Apply a material without setting anything on it. Then try setting one by one `diffuseColor, specularColor, emissiveColor, ambientColor` with `Color3(1, 1, 1)` and only the `emissiveColor` had an effect. All the others, didn’t change anything

---

<div class="post-metadata">

**Author:** ![maxime1992](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/maxime1992/32/4922_2.png) [@maxime1992](https://forum.babylonjs.com/u/maxime1992)\
**Post date:** [December 4, 2022, 11:31am UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/11 "2022-12-04T11:31:45Z")

</div>

@mawa

> first I godda say you did a very good debugging on this peculiar topic of using shadows with a directional light

Thanks for the kind words! That said, I only followed exactly what @Evgeni_Popov wrote [here](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/2), which was perfect 👌

> What you need to understand here is that the darkness of the shadow uses the emissive. Understand the emissive color ‘emits a color’ that will superseed your shadow. By making a white emissive with a default level 1, you are emitting strong white color against the light/shadow

Ok that makes sense! Thanks

> If the light is obstructed from the other side, well… it is 😉 So, adding a ‘global type’ of light to your scene is I believe the way to go

Makes sense as well!

> set an intensity lower than 0 (i.e. -1) on the light that is just for shadow casting

Oooow. Good to know!

---

<div class="post-metadata">

**Author:** ![mawa](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/mawa/32/12384_2.png) [@mawa](https://forum.babylonjs.com/u/mawa)\
**Post date:** [December 4, 2022, 11:32am UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/12 "2022-12-04T11:32:21Z")

</div>

Your active material in this screenshot has a real funny name. Again, I encourage you to set-up a playground (shouldn’t be too hard at this stage). With this, we will likely spot the issue within minutes.

---

<div class="post-metadata">

**Author:** ![maxime1992](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/maxime1992/32/4922_2.png) [@maxime1992](https://forum.babylonjs.com/u/maxime1992)\
**Post date:** [December 4, 2022, 11:45am UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/13 "2022-12-04T11:45:52Z")

</div>

@Evgeni_Popov thanks for explaining how to upload a mesh on external service!

I’ve managed to get a repro in the online playground 😄 ! I thought it might make your life easier while trying to help me out 🙏!

**Live repro: [https://playground.babylonjs.com/#SLUR5N#1](https://playground.babylonjs.com/#SLUR5N#1)**

_EDIT: (oh, @mawa I just saw your comment, after posting that! Good timing ha)_

---

<div class="post-metadata">

**Author:** ![mawa](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/mawa/32/12384_2.png) [@mawa](https://forum.babylonjs.com/u/mawa)\
**Post date:** [December 4, 2022, 12:13pm UTC](https://forum.babylonjs.com/t/shadow-not-behaving-as-expected/36213/14 "2022-12-04T12:13:35Z")

</div>

Yes, so it really is the issue from having no lights on these materials.  
Here I quickly added a hemi.

> **[Babylon.js Playground](https://playground.babylonjs.com/#SLUR5N%232)**
>
> Babylon.js playground is a live editor for Babylon.js WebGL 3D scenes

The rest depends on how you want your surfaces lit and the darkness (and type of) shadows.

**Edit:** OK, since it’s sunday 🕶 it might be a good time to experience a little with shadows and lights, so I quickly enhanced the PG adding a couple more lights and a second shadow generator. I have also added some options you can play with.  
I encourage you to experience with these lights, set their intensity, exclude or include meshes, change the lights position, direction and intensity. Also, for the different types of shadows #realistic (hard, soft…) I would recom you take a look at the doc to see what parameters you can set (and there are many). You can also try adding shadow from a spotlight and changing the light angle to see what it does. Just keep in mind that 1) light only adds to light 2) the further the light, the bigger the area that is lit (eventually exploding a material/surface and in any case flattening the light on the volume)

> **[Babylon.js Playground](https://playground.babylonjs.com/#SLUR5N%234)**
>
> Babylon.js playground is a live editor for Babylon.js WebGL 3D scenes

**Edit 2:** If you wish, you can see some of the ‘semi-realistic’ shadows I created in my demos. The first demo (snowball) includes an animated light/shadow from the sun using a directional light (press KB 1 to 7 to change time of day):

> [@Snowball Demo - "Winter is Back' (updated for BJS version 5.6)](https://forum.babylonjs.com/t/snowball-demo-winter-is-back-updated-for-bjs-version-5-6/30379):
>
> Hello BJS Community, I have finally decided (and found some time) to update my first real demo for BJS ‘[Project Snowball Demo](https://forum.babylonjs.com/t/project-snowball-winter-is-coming-new-update-v-0-8-5-3-bjs-v5-6/15925)’. The [link to the demo](https://media-geneva.ch/demos/bjs/snowball/psa.html) is unchanged. The Snowball Demo, although quite old and unexperienced at the time of creation, is still showing in the top 50 most viewed, so it definetely deserved this (late timer_clock, sry) update. Work is not all done yet. This is an intermediate update (about 60% complete). Updating this first demo of mine with all…

> [@'Project Chair' in preview environment - A Designer's playground open to all](https://forum.babylonjs.com/t/project-chair-in-preview-environment-a-designers-playground-open-to-all/20682):
>
> Good Day Dear BJS fellow Contributors, Hope yours are all well. I have been long asking myself what I should be doing with my project initiated mid-february 2021, first called ’ Project Chair - Sketching a 3D commerce XP in 60h '. The first thing I can say towards this exercise is that I’ve both failed and/or succeeded in this. It all depends on your definition of ‘sketching’ and ‘experience’, I believe wink In short: Yes, it’s possible to make good use of BJS to sketch both a visual and a p…

> [@(Inspired by) BSA Bantam D1 Motorcycle project now in preview](https://forum.babylonjs.com/t/inspired-by-bsa-bantam-d1-motorcycle-project-now-in-preview/28399):
>
> Hello BJS Community, I know it has been a long (very long) time since I last posted here. My apologies for that. The point is, when I come to the forum, I tend to just look at all the amazing things you guys do astonished, post a few shit comments, answer a couple of questions if I can and next thing I realize, I don’t really work my own project wink Despite for not being present in the forum, I haven’t quit BJS-ing. Neither did I start growing potatoes in my backyard like I said I would i…