Hdri Lightmap

[Suyay Escarsega]

Idid some research and had some thoughts about my problem,

a.Is there any problem laying 32 bit lightmap on 8 bit srgb texture? From my understand, when applying 32 bit hdr(linear color) lightmap to texture(8 bit srgb, gamma corrected), THREE should be able to automatically transfer srgb to linear color space. So that the lighting calculation should be correct. Hence the sRGB texture should be fine. But I am not sure how THREE will treat HDR(linear color space). I looked in to the glsl shader on github. Here are how THREE handle map(texture) and lightmap in shader.

From my understand(sorry if I am wrong), map were transferred to linear and lightmapwere transferred as well. Hence , my lightmap were transferred twice, which result in wrong results.

If my thoughts were correct, then all I need to do is transfer my linear hdr lightmap to sRGB. Then it should work? But I am afraid the lost data will result in bad rendering result in THREE.

Trying to do the same thing but having trouble getting an HDR to load and respond to exposure values in the renderer. Did you pack the texture as a ktx2? I think RGBE texture loading is deprecated in latest 3js.

The next small issue is probably of the same root cause but again, ive read similar posts but all solutions seem to be increasing samples or resolution. Which are both pretty much maxed out.

Its the small black lines where two surfaces join, this could also be due to a simplified mesh leaving gaps in the geometry?

(New users can only attach one image so I will try to post in the comments)

Then I am using the new water material type. I have yet to figure it out properly so any added info on that would be great. But as it stands, the water is reflecting the sofa here as if it were above it. Should my light probe be lower or is this the only outcome you can expect. Is there a way to reflect something that is sitting on a mirrored surface?

(New users can only attach one image so I will try to post in the comments)

And finally (finally) my HDRI map even in high resolution is coming out very blurred. Is there a way to maintain a high quality image where you can see out of the otherwise closed scene?

(New users can only attach one image so I will try to post in the comments)

The dark edges are visible in places where the geometry is partially occluded. Because lightmap pixels have limited resolution one pixel can cover area that is fully illuminated and area that is occluded. Such pixel will be darker than fully illuminated pixels. Furthermore, when lightmap data is used by shaders, the data from four neighboring pixels is interpolated. Without such interpolation there would be hard checkered pattern instead of smooth changes between pixels. Because of the interpolation, if a bright pixel has occluded dark neighbors, these neighbors will cause the pixel to be darker close to the pixel edges.

In some cases you can improve the geometry to fix these problems. For example, make sure the furniture is always above the floor, if a small part of a furniture is below the floor, it can be baked as dark, and can cause the darkness to leak above the floor level.

As for the HDRI, the sky texture resolution for desktops is limited to 4096x2048. Close to 100% of devices support such size, but only about 60% support larger size (these stats are available here: _TEXTURE_SIZE). If your windows are facing only on one side of the world, you could put a texture on a large rectangle object visible through the windows, instead of using a 360 panorama (for example this scene: 3D scene does this). If you do so, set lightmap resolution to 0 for such a rectangle to save lightmap space and baking time.

Do you have a fix for the dark edges around some pieces of furniture? Would that get sorted in a smaller scene with therefore a better resolution? This is the one thing really holding me back at the moment and it would be great to know how to proceed.

To improve the reflection positioning in the water, move the light probe down and enable a bounding box for it with dimensions like: min: 8, -11, 0, max: 14, -5, 4

Try also using much darker color for the water, this way the reflection color will be taken from the surrounding in much larger extend.

I am trying to bake hard sunlight from an hdr image on android but it looks like the lightmapper uses the compressed ldr image for the bake instead of the original hdr image. I have tried the different compression settings on the image but could not find one that allows me to bake hard light and shadow from an hdr image. This is not an issue with the compression of the lightmap as i can bake hard shadows with a directional light.

I am new to the forums but have been lurking around in the shadows for awhile now, often using this site to find solutions to many problems I have faced in the last few years. I am hoping you can provide some insight into my current problem as I have tried and failed to rectify this issue over the last few days, resulting in me to finally make my presence known...

I had some downtime so was playing around with a "daylight" scene and using HDRI map to light and also provide reflections for my scene. Normally HDRIs provide soft shadows for lighting which I never had problems with, but I really wanted to speed up daylight workflow without using Daylight System just swap HDRI maps instead to get soft shadows for those cloudy days or strong clear day sun shadows.

I placed the hdri map inside Environment Map, and told Skylight to use it. Did my test render and the hdri map is perfect- gives me nice strong shadows! Yet my test Arch&Design material with blurred glossiness is looking awful, and speckled no matter how many samples I give it. It seems that the lower the glossiness value is the more speckled the sun reflection appears in the render.

Why is this happening? Is it at all possible to sort out? (The only way I could get more blurry reflections was to blur the hdri map by tons, but then my sun shadows become blurry too, which is the opposite of what I wanted to produce)

Using this method, have you been able to get strong shadows (similar to vray) when only using the HDRI map/skydome combo to light your scene? If so, have you done this in 3ds max versions prior to 2014?

Unfortunately I am already using the Autodesk recommended way of using HDRI's after watching their youtube video on introducing IBL method as it seems to work best with HDRI workflow. (Skylight is using scene environment) I never had problems with normal interior renders where soft shadows are more desired, only with strong sun + shadow HDRI.

I managed to achieve a more desired look by Creating 2 HDRI materials, keeping original in Skylight- Sky Color Map- so it won't use it for reflections. Then creating a copy of the material and setting Bur value to 100 and placing it in the Environment Map slot. This way there's no more speckles from the sun...The lower the Blur value the more speckles I get, hence why 100 produced best results.

If I load the Environment map HDRI as 16bit and not 32 real Pixels (in the Setup of HDRI load settings), I am still getting correct non-blurred reflections without the speckles! So I just need to have 2 seperate HDRI materials, one at correct pixel depth and one lower.

I had default sampling per pixel setting. Min 1 and Max 128 I think, sampling quality set at 8. I messed around with increasing the min and max values as you suggested but no change in speckles effect.

I found out I can Clamp my HDRI which is used for reflections, which gets rid of these speckles! Just have to make sure I'm not clamping the Skylight map HDRI to get those strong sharp shadows. (reference )

Ps. I wrote another solution to this a few days ago, it hasn't been approved yet by moderators but it's basically to load in HDRI not at Real Pixel 32 bpp, but at 16 bit/chan linear, this also solves the speckling. Once again, keep original real pixels HDRI for Skylight map.

I haven't been able to test this much further, but yes I noticed "clamp" option makes reflections more dull, especially the bright whites. I think, and don't quote me on this, but a better option was to load HDRI map for reflections only as 16bit and not 32? This way there was no speckles but colours were bright and not dull. Again, I could be wrong as I don't remember which option was the best, as I never ended up working with the original test scene again...

yes, very helpful thread, thanks for your work. i do find that the option of two maps being used helpful! based on that, i've tried setting my frame buffer window to be 16bit and that seems to have similar results without having to use two maps. thanks.

HDR 2 RGBM is addon for encoding HDR image to RGBM format. I created this addon because BGE or viewport cannot read HDR texture properly (RGB value always clamped at 1.0). RGBM format can encode any HDR image to standard 8-bit PNG image. This addon can decode RGBM in realtime too, so it can be useful for lightmap or environment map on viewport or BGE.

I have an light probe image as environment map, I want to render my image at 3ds Max based on the lighting cast by the environment map, so that the environment map can work as a light source. I tried skylight and checked its documentation, but it did not clarify how it works. Is there a way to do so? Thanks.

Thanks a lot for your reply. The problem I am suffereing now is that I want to use the environment map as the only light source, which can cast relatively strong shadow. Is that possible? It seem in the daylight system, it do have skylight and directional light at the same time, which means we have to have another light source to light the scene. Is that right?

The only light in the scene is the Skylight using the hdri image in the Map slot. I didn't use the Preset system. I only entered the Exposure value at 2.0. I used the jpeg bg for this, but if you have access to .hdr then that woul dbe even better. You would need to use the same image as the Environment Map. You may need to adjust the Exposure setting and the Skylight's Multiplier settings to achieve the desired result.

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