Light object "Spot" behaves like "Point" #115035

New Issue

Gordon Brinkmann · 2023-11-17T08:57:20+01:00

Gordon Brinkmann commented

2023-11-17 08:57:20 +01:00

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 536.23

Blender Version
Broken: version: 4.0.0, branch: blender-v4.0-release, commit date: 2023-11-13 17:26, hash: 878f71061b8e
Worked: 3.6.5

Short description of error
If you place a "Spot" in a scene (especially within a volumetric fog like a cube with Principled Volume material), the light produces a visible sphere if the Radius is larger than 0. Even without volumetrics, a "Spot" will shine light on meshes lying on the opposite side of the direction it is pointing to if this mesh lies within the radius.

This is the same behavior as the "Point" shows, where a mesh will be lit up as long as it's within the radius of the light, no matter if the mesh occludes the light from the point of view - I can relate to that if this is supposed to be a large light bulb or whatever. Admittedly though the beam of light coming from the "Spot" is now better representing the radius - but I think a spotlight should rather have a 2D circle as base, not a 3D sphere.

However a spotlight creates a directional light which can have a large diameter for example in large searchlights, but in 4.0 this now means a mesh which would act as the surrounding lamp object producing the light would have to be "deep" enough to cover up the whole sphere of the spotlight. Or in volumetrics, looking at the lamp from the side would probably show a half sphere coming out of the lamp.

Exact steps for others to reproduce the error
Put a light object "Spot" in a scene. Place it in a volumetrics cube or place a mesh object to occlude the view on it within the light's radius.

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 536.23 **Blender Version** Broken: version: 4.0.0, branch: blender-v4.0-release, commit date: 2023-11-13 17:26, hash: `878f71061b8e` Worked: 3.6.5 **Short description of error** If you place a "Spot" in a scene (especially within a volumetric fog like a cube with Principled Volume material), the light produces a visible sphere if the Radius is larger than 0. Even without volumetrics, a "Spot" will shine light on meshes lying on the opposite side of the direction it is pointing to if this mesh lies within the radius. This is the same behavior as the "Point" shows, where a mesh will be lit up as long as it's within the radius of the light, no matter if the mesh occludes the light from the point of view - I can relate to that if this is supposed to be a large light bulb or whatever. Admittedly though the beam of light coming from the "Spot" is now better representing the radius - but I think a spotlight should rather have a 2D circle as base, not a 3D sphere. However a spotlight creates a directional light which can have a large diameter for example in large searchlights, but in 4.0 this now means a mesh which would act as the surrounding lamp object producing the light would have to be "deep" enough to cover up the whole sphere of the spotlight. Or in volumetrics, looking at the lamp from the side would probably show a half sphere coming out of the lamp. **Exact steps for others to reproduce the error** Put a light object "Spot" in a scene. Place it in a volumetrics cube or place a mesh object to occlude the view on it within the light's radius.

spot_comparison.jpg

332 KiB

spotlight.blend

1.0 MiB

Gordon Brinkmann added the

labels 2023-11-17 08:57:20 +01:00

Iliya Katushenock commented

2023-11-17 09:05:13 +01:00

I can't confirm, however this issue has been reported before, see #114241. Will merge reports. Please subscribe in #114241 if you want to see further updates

Iliya Katushenock closed this issue

2023-11-17 09:05:16 +01:00

Blender Bot added

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labels 2023-11-17 09:05:18 +01:00

Iliya Katushenock added

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labels 2023-11-17 09:05:35 +01:00

Gordon Brinkmann commented

2023-11-17 10:46:32 +01:00

I can't confirm, however this issue has been reported before, see #114241. Will merge reports. Please subscribe in #114241 if you want to see further updates

You can't confirm? Have you seen the comparison image and looked at the file? The issue you have merged this to is about Point lights. I totally understand and agree why this is done with Point lights and it makes totally sense for PBR, however I'm talking about the Spot light. This light source in itself is not how lights work in reality, so I do not understand why it has to act like a Point light which it is not.

> I can't confirm, however this issue has been reported before, see #114241. Will merge reports. Please subscribe in #114241 if you want to see further updates You can't confirm? Have you seen the comparison image and looked at the file? The issue you have merged this to is about Point lights. I totally understand and agree why this is done with Point lights and it makes totally sense for PBR, however I'm talking about the Spot light. This light source in itself is not how lights work in reality, so I do not understand why it has to act like a Point light which it is not.

Fernando Alcala commented

2023-11-17 21:35:44 +01:00

The spot light was changed to just be a point light with an angle #109329

Gordon Brinkmann commented

2023-11-20 07:40:16 +01:00

The spot light was changed to just be a point light with an angle #109329

I know it did from the behavior it showed, I just don't see why. As I commented under #114241 to which my report was merged, having a spot light in itself is not physically accurate, so I cannot understand why it has to get the same sphere properties of a point light, when it's not emitting light like a point light and this change also makes it unusable in scenes where it was perfectly working before.

> The spot light was changed to just be a point light with an angle #109329 I know it did from the behavior it showed, I just don't see why. As I commented under #114241 to which my report was merged, having a spot light in itself is not physically accurate, so I cannot understand why it has to get the same sphere properties of a point light, when it's not emitting light like a point light and this change also makes it unusable in scenes where it was perfectly working before.

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Light object "Spot" behaves like "Point" #115035