Blender 4.0: Cycles - Point lights Viewport shape and size regression #112005

New Issue

David Black · 2023-09-06T08:25:27+02:00

David Black commented

2023-09-06 08:25:27 +02:00

System Information
Linux Mint 21.2 Cinnamon kernel 6.2.0-32
3400G

Broken
blender-4.0.0-alpha+main.b5c89822ac40-linux.x86_64-release.tar.xz

Oldest tested (2023-07-21)
blender-4.0.0-alpha+main.3e88a2f44c41-linux.x86_64-release.tar.xz

Worked
blender-3.6.3-candidate+v36.2fc04eaf4310-linux.x86_64-release.tar.xz

Short description of error:
'Viewport Shading' Cycles 'Rendered' - incorrect Point lights shape in front & side views, plus Orthographic size.

Also recently encountered in a production scene, Point lights now render slightly larger, outside their Viewport bounds (appears to have been reported, so only mentioned here in case relevant).

Possibly connected with previous #108505, #108506 lights improvements, @weizhen and @Alaska possibly able to help? Thank you in advance!

Exact steps

Compare following .blend file in both 3.6 and 4.0 using 'Viewport Shading' (Cycles) Rendered.
Point lights Cycles regression.blend
While Cycles Viewport is rendering, toggle Perspective / Orthographic using 5 on numerical keypad.

Kind regards.

Blender version	Perspective	Orthographic
Blender 3.6
Blender 4.0

**System Information** Linux Mint 21.2 Cinnamon kernel 6.2.0-32 3400G **Broken** blender-4.0.0-alpha+main.b5c89822ac40-linux.x86_64-release.tar.xz Oldest tested (2023-07-21) blender-4.0.0-alpha+main.3e88a2f44c41-linux.x86_64-release.tar.xz **Worked** blender-3.6.3-candidate+v36.2fc04eaf4310-linux.x86_64-release.tar.xz **Short description of error:** 'Viewport Shading' Cycles 'Rendered' - incorrect Point lights shape in front & side views, plus Orthographic size. Also recently encountered in a production scene, Point lights now render slightly larger, outside their Viewport bounds (appears to have been reported, so only mentioned here in case relevant). Possibly connected with previous #108505, #108506 lights improvements, @weizhen and @Alaska possibly able to help? Thank you in advance! - Exact steps 1. Compare following .blend file in both 3.6 and 4.0 using 'Viewport Shading' (Cycles) Rendered. [Point lights Cycles regression.blend](/attachments/30a6c8c0-8f38-485b-bf08-877c88efe4e4) 2. While Cycles Viewport is rendering, toggle Perspective / Orthographic using 5 on numerical keypad. Kind regards. |Blender version|Perspective|Orthographic| |-|-|-| |Blender 3.6|![1 Blender 3.6 - Perspective.jpg](/attachments/ca0e9124-2adc-4ff3-afd4-dfbad3eb756d)|![2 Blender 3.6 - Orthographic.jpg](/attachments/4a03f684-16a5-439d-9447-e82771c5d471)| |Blender 4.0|![3 Blender 4.0 - Perspective.jpg](/attachments/49273278-d602-4b2c-b256-481731c1104a)|![4 Blender 4.0 - Orthographic.jpg](/attachments/c3be34b7-7f3a-4ac0-9042-c5160cafab07)|

Point lights Cycles regression.blend

101 KiB

3 Blender 4.0 - Perspective.jpg

393 KiB

4 Blender 4.0 - Orthographic.jpg

374 KiB

2 Blender 3.6 - Orthographic.jpg

360 KiB

1 Blender 3.6 - Perspective.jpg

394 KiB

David Black added the

labels 2023-09-06 08:25:28 +02:00

David Black changed title from ~~Blender 4.0: Cycles - Point lights Viewport regression~~ to Blender 4.0: Cycles - Point lights Viewport shape and size regression

2023-09-06 08:28:15 +02:00

Alaska commented

2023-09-06 09:58:26 +02:00

I didn't work on the recent changes to the point lights, but I just wanted to bring up a few points about this.

Many of the issues in orthographic view in 4.0 seem to be precision related because as the distance between ray start and the light decreases, the issues start to disappear. It's just way more noticeable for the camera ray in orthographic mode compared to other things (E.G. Seeing a small light in the reflection from an object many hundreds to thousands of meters away). Quick investigations point to it being a precision issue in the ray_sphere_intersect() function when working with long rays. Note: I have attached a video to this comment showing that the issues are somewhat precision related.

Also recently encountered in a production scene, Point lights now render slightly larger, outside their Viewport bounds (appears to have been reported, so only mentioned here in case relevant).

I believe this is expected. In Blender 3.6, the point light rendered as a disk orientated towards the ray/camera. The viewport representation is a hollow disk (circle) orientated towards the camera. Due to the point light and the viewport representation being basically the same thing, they match. In Blender 4.0, the point light is now a sphere, while the viewport representation is still a hollow disk. This means that as you get close to the point light, the two will deviate from each other due to perspective distortion (I believe this is the right name?).

I didn't work on the recent changes to the point lights, but I just wanted to bring up a few points about this. - Many of the issues in orthographic view in 4.0 seem to be precision related because as the distance between ray start and the light decreases, the issues start to disappear. It's just way more noticeable for the camera ray in orthographic mode compared to other things (E.G. Seeing a small light in the reflection from an object many hundreds to thousands of meters away). Quick investigations point to it being a precision issue in the `ray_sphere_intersect()` function when working with long rays. Note: I have attached a video to this comment showing that the issues are somewhat precision related. >Also recently encountered in a production scene, Point lights now render slightly larger, outside their Viewport bounds (appears to have been reported, so only mentioned here in case relevant). - I believe this is expected. In Blender 3.6, the point light rendered as a disk orientated towards the ray/camera. The viewport representation is a hollow disk (circle) orientated towards the camera. Due to the point light and the viewport representation being basically the same thing, they match. In Blender 4.0, the point light is now a sphere, while the viewport representation is still a hollow disk. This means that as you get close to the point light, the two will deviate from each other due to perspective distortion (I believe this is the right name?).

Blender 4.0 precision issues demo.mp4

5.4 MiB

Alaska added

and removed

labels 2023-09-06 09:59:08 +02:00

Philipp Oeser commented

2023-09-06 13:31:33 +02:00

Will still raise prio here to get some more insights from the module (since it is a recent change), can be lowered again if appropriate.

CC @weizhen

Will still raise prio here to get some more insights from the module (since it is a recent change), can be lowered again if appropriate. CC @weizhen

Philipp Oeser added

and removed

labels 2023-09-06 13:31:43 +02:00

Weizhen Huang self-assigned this 2023-09-06 15:46:42 +02:00

Alaska referenced this issue

2023-09-06 15:46:45 +02:00

Cycles: Deduplicate sphere intersection test #112031

Weizhen Huang referenced this issue

2023-09-06 15:50:11 +02:00

Cycles: Deduplicate sphere intersection test #112031

Alaska referenced this issue

2023-09-06 15:52:37 +02:00

Cycles: Deduplicate sphere intersection test #112031

Weizhen Huang referenced this issue from a commit

2023-09-06 16:24:06 +02:00

Fix #112005: increase `ray_sphere_intersect()` precision

Weizhen Huang closed this issue

2023-09-06 16:24:08 +02:00

Blender Bot added

and removed

labels 2023-09-06 16:24:11 +02:00

David Black commented

2023-09-10 16:51:18 +02:00

Apologies for a tardy reply.

Thank you @Alaska for your detailed reply and creating a helpful video, much appreciated! Guess next step is for Workbench to switch to a Viewport sphere overlay.

Thanks also @lichtwerk for your input, and bug reports dedication.

Finally, thank you @weizhen for the rapid fix, you truly are a gifted developer!

Kind regards.

Apologies for a tardy reply. Thank you @Alaska for your detailed reply and creating a helpful video, much appreciated! Guess next step is for Workbench to switch to a Viewport sphere overlay. Thanks also @lichtwerk for your input, and bug reports dedication. Finally, thank you @weizhen for the rapid fix, you truly are a gifted developer! Kind regards.

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Blender 4.0: Cycles - Point lights Viewport shape and size regression #112005