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Why the Heck Didn't Anyone Teach Me About HDRIs?!

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  • nemesis10nemesis10 Posts: 3,774
    Divamakeup said:
    nemesis10 said:

    Just in case, hopefully people know how to turn off the headlamp before rendering; it is for posing and, unfortuntately, is a very unsubtle light which screws with the diffuse light from the HDRI.

    I find headlamp quite adequate for many renders. Most of my renders have the headlamp on at various strengths. It depends on what you're shooting for with your renders. Most of the time I'm after a photograph type of look, and I think headlamp helps achieve that look. I could set up a similar frontal light and use that, but prefer to use the headlamp as it's easier and moves with the camera. There really is no "right or wrong" way to do 3D renders, imo - as long as you're getting the look you're after everything's fair game to use. Like most art, it's subject to personal tastes and preferences. :)  It's always fun to experiment with different things and different settings and see what you, personally, like. In the end it's all ones and zeros and whatever you want to do to get the render to look the way that you like it, it's all good. :)

    It definitely adds a sort of flashbulb quality but often washes away fine diffuse light in my renders....  I can never make anything look too realistic with it shining...

  • nicsttnicstt Posts: 11,715
    donalddade said:
    nicstt said:

    Well, obviously, we didn't know you didn't know.

    ... And if you'd known you didn't know you could have asked us about them. laugh

    Had I known that you didn't know that I didn't know, I would have known to let you know :)

    I think the only thing that Donald Rumsfeld ever said where I could actually follow his logic was his comment about unknown unknowns, and strangely, the time when he was making the most sense is what his detractors used to discredit him.

    Indeed.

  • gilamoureuxgilamoureux Posts: 21
    Horo said:

    You can save a scene or a sky in Bryce as HDRI (RGBE RLE2 as Carrara, DS Iray/3DL use) but the data is derived from a 48 bit render. The next issue is you cannot directly render a spherical panorama, only a cylindrical one. We have a product to bolt a lens in front of the camera that renders directly a spherical panorama. But Bryce limits to 4000 pixels wide so the pano can only be 4000 x 2000 pixels. You can, of course, render the 6 cube faces and assemble the pano in an external program. I made (faked) many HDRIs from Bryce renders with a dynamic range of up to several million to one.

    Making HDRIs from photographs usually yield better results; meanwhile, I made around 300 indoor and outdoor ones. Though it's nice to have a high dynamic range, particularly if the sun is in the scene, the HDRI often doesn't provide enough ambient light. A lower dynamic range gives nice ambient light but an additional key light may be necessary.

    The size of an HDRI usually doesn't matter much as far as light generation is concerned but size is key if it is used to render as backdrop. You need at least 1 pixel in the HDRI for 1 pixel in the rendered scene. If your HDRI width is 3600 pixels and you use a 28 mm lens, the horizontal field of view is about 60 degrees, a sixth of the HDRI is visible, which means 600 pixels. And that's the maximum width you can render your scene with a sharp backdrop.


    This is very good info Horo. I didn't really think about the ambiant lighting vs dynamic range, or even the HDRI width vs camera lens idea. Regarding the size of the HDRI file I find that if only the sky is used as backdrop I don't mind if it's not very sharp.

    Is it possible to render the HDRI file with different exposure settings in Bryce to combine them to increase the range?

  • HoroHoro Posts: 11,343

    gilamoureux - Yes. It's always cheating, though. Bryce lights work linear. If you half the light output, you get half of the light. There's no gamma. So it's easy to dim a room or brighten it up in 1 or 2 f-stops, save the renders and then combine them to an HDRI with an external program (HDRShop, Picturenaut, etc). The catch are the visible lights. If you have visible lights (or a visible sun), you need to dim them differently, maybe even almost not at all through the different f-stop renders so you get them very much brighter than the environment.

  • TaozTaoz Posts: 10,256

    I rarely buy HDRIs in the DAZ store because the quality is often rather poor IMO.  Among others it shows as compression artifacts which are especially visible in the sky, making it look "dirty".   

    Here are two examples showing how much the quality can differ, the first is several years old, the second one purchased yesterday (you'd expect quality to improve over the years, right?).  Both are rendered in perspective view with the same settings. I think they speak for themselves, the first one shows how it can be done, the second how it's often done (if I were DAZ I would have rejected it).

     

     

     

    dhtdr_mauia.png
    1455 x 950 - 2M
    swedish_rocks.png
    1455 x 950 - 2M
  • Sven DullahSven Dullah Posts: 7,621
    Taoz said:

    I rarely buy HDRIs in the DAZ store because the quality is often rather poor IMO.  Among others it shows as compression artifacts which are especially visible in the sky, making it look "dirty".   

    Here are two examples showing how much the quality can differ, the first is several years old, the second one purchased yesterday (you'd expect quality to improve over the years, right?).  Both are rendered in perspective view with the same settings. I think they speak for themselves, the first one shows how it can be done, the second how it's often done (if I were DAZ I would have rejected it).

     

     

     

    surprise, that's really bad...what was the resolution of that HDRI?

  • HoroHoro Posts: 11,343

    It appears as if the second was a JPG re-saved as HDRI. Such can often be observed.

  • HylasHylas Posts: 5,223

    Ugh. I've seen this in freebie HDRI's but you really shouldn't ask money for it.

  • TaozTaoz Posts: 10,256
    Sven Dullah said:
    Taoz said:

    I rarely buy HDRIs in the DAZ store because the quality is often rather poor IMO.  Among others it shows as compression artifacts which are especially visible in the sky, making it look "dirty".   

    Here are two examples showing how much the quality can differ, the first is several years old, the second one purchased yesterday (you'd expect quality to improve over the years, right?).  Both are rendered in perspective view with the same settings. I think they speak for themselves, the first one shows how it can be done, the second how it's often done (if I were DAZ I would have rejected it).

     

     

     

    surprise, that's really bad...what was the resolution of that HDRI?

    I don't know, where can you see that?  The size is around 55 MB.

  • TaozTaoz Posts: 10,256
    edited August 2019
    Horo said:

    It appears as if the second was a JPG re-saved as HDRI. Such can often be observed.

    AFAIK the set is made with an Insta360 One X, a 16 MP $500 camera with HDR support:  https://www.insta360.com/product/insta360-onex 

    There is a camera included in the HDRI set, it makes it look a bit better by "downsizing" the image, but it distorts the characters.

     

    swedish_rocks_2.png
    1455 x 950 - 2M
    Post edited by Taoz on
  • ArtiniArtini Posts: 10,306
    edited August 2019

    I have rendered 360 degrees panorama in Unity and saved it as .EXR with resolution 8192x4096.

    Then I have rendered Diego 8 with it in Daz Studio iray, but the EXR did not provided enough light itself:

    image

    so I have turned on Head Lamp in Camera settings:

    image

    Diego802pic02headLampOff.jpg
    1400 x 1080 - 465K
    Diego802pic01headLampOn.jpg
    1400 x 1080 - 471K
    Post edited by Artini on
  • ArtiniArtini Posts: 10,306
    edited August 2019

    Any tips on how to improve render with such panoramas to blend better Daz characters in it?

    Post edited by Artini on
  • HoroHoro Posts: 11,343

    I don't know wether Unity internally renders with an extended gamut. Saving a render as HDR, EXR, or 96-bit TIF doesn't make it an HDRI. It's just the render saved in another image file format, HDRIs usually without gamma. Open your EXR panorama in an HDRI capable graphics program and measure the pixel values. The pixel values of the lit signs should be much higher (100 times or more) than the street. You panorama looks evenly lit and should give an even light on Diego. There may be a control in Studio/Iray to boost the output (I don't know DS good enough), and if not, you can multiply the pixel values in an HDRI capable graphics program. This doesn't change the dynamic range, only the light output. In case Unity doesn't render with an extended gamut (e.g. high dynamic range), you have to render your panorama several times with different light settings to simulate different f-stops, than add them. Otherwise, you have just an ordinary LDRI panorama saved in a HDRI file format. They usually give nice ambient light.

  • TaozTaoz Posts: 10,256

     

    Taoz said:
    Sven Dullah said:
    Taoz said:

    I rarely buy HDRIs in the DAZ store because the quality is often rather poor IMO.  Among others it shows as compression artifacts which are especially visible in the sky, making it look "dirty".   

    Here are two examples showing how much the quality can differ, the first is several years old, the second one purchased yesterday (you'd expect quality to improve over the years, right?).  Both are rendered in perspective view with the same settings. I think they speak for themselves, the first one shows how it can be done, the second how it's often done (if I were DAZ I would have rejected it).

     

     

     

    surprise, that's really bad...what was the resolution of that HDRI?

    I don't know, where can you see that?  The size is around 55 MB.

    6080x3040

  • ArtiniArtini Posts: 10,306
    edited August 2019
    Horo said:

    I don't know wether Unity internally renders with an extended gamut. Saving a render as HDR, EXR, or 96-bit TIF doesn't make it an HDRI. It's just the render saved in another image file format, HDRIs usually without gamma. Open your EXR panorama in an HDRI capable graphics program and measure the pixel values. The pixel values of the lit signs should be much higher (100 times or more) than the street. You panorama looks evenly lit and should give an even light on Diego. There may be a control in Studio/Iray to boost the output (I don't know DS good enough), and if not, you can multiply the pixel values in an HDRI capable graphics program. This doesn't change the dynamic range, only the light output. In case Unity doesn't render with an extended gamut (e.g. high dynamic range), you have to render your panorama several times with different light settings to simulate different f-stops, than add them. Otherwise, you have just an ordinary LDRI panorama saved in a HDRI file format. They usually give nice ambient light.

    Thanks a lot, Horo, for such valuable information.

    I did not know, that one can find such information about the pixel values.

    The panorama was rendered in Unity in the latest HDRP pipeline, but the lights was not fully baked up.

    With complex scenes baking could take many hours. I have just checked and it says around 5 hours to finish.

    There is a GPU based baking addon for Unity, but I have not purchased it yet.

     

    Post edited by Artini on
  • ArtiniArtini Posts: 10,306

    Just read, what does HDRP means and it is High Definition Render Pipeline,

    so I do not know, if it really could create HDRI images.

     

  • ArtiniArtini Posts: 10,306

    Now I have found, that the GPU lightmapper is included in Unity and I switched to it.

    What a difference. Now baking will take only a couple of minutes.

    I will make another panorama and see what happens.

     

  • ArtiniArtini Posts: 10,306

    It finished. Total baking time 4 minutes 14 seconds. I like it.

     

  • ArtiniArtini Posts: 10,306

    ... but there is no improvement on the render.

     

  • ArtiniArtini Posts: 10,306
    edited August 2019

    I have tested EXR rendered in Octane and none of them provided enough light to the scene.

    Below is Diego 8 render with one of Cake and Bob HDRIs:

    image

    Diego801pic01.jpg
    1080 x 1080 - 494K
    Post edited by Artini on
  • MattymanxMattymanx Posts: 6,996
    edited August 2019

    HDRIs are very good for lighting.

    For the store here at Daz, I will personally recommend:

    https://www.daz3d.com/dimensiontheory

    https://www.daz3d.com/cake-one

     

    For outside Daz3D, I would personally recommend HDRIHaven.com  I use a lot of their's now in test renders and promos.  They are very good.

    For those who dont know, you can adjust the strength of the HDRI on the Environment tab in the Render settings.  Right where you see the thumbnail for the HDRI, there is a strength setting.  I use that instead of adjusting the exposure.

     

    This is one of my latest images.  Its uses this HDRI from HDRIHaven - https://hdrihaven.com/hdri/?h=hamburg_hbf - There are 3 other versions of it on my Artstation account.  Click the banner below to go there.

    https://www.daz3d.com/gallery/images/848416/

    Post edited by Mattymanx on
  • ArtiniArtini Posts: 10,306
    edited August 2019
    Mattymanx said:

    HDRIs are very good for lighting.

    For the store here at Daz, I will personally recommend:

    https://www.daz3d.com/dimensiontheory

    https://www.daz3d.com/cake-one

     

    For outside Daz3D, I would personally recommend HDRIHaven.com  I use a lot of their's now in test renders and promos.  They are very good.

    For those who dont know, you can adjust the strength of the HDRI on the Environment tab in the Render settings.  Right where you see the thumbnail for the HDRI, there is a strength setting.  I use that instead of adjusting the exposure.

     

    This is one of my latest images.  Its uses this HDRI from HDRIHaven - https://hdrihaven.com/hdri/?h=hamburg_hbf - There are 3 other versions of it on my Artstation account.  Click the banner below to go there.

    https://www.daz3d.com/gallery/images/848416/

    Sure, you are right.

    But I have already bought most of the HDRIs available here in Daz shop,

    and now I want to create some new of my own.

    I have only recently discovered, that free Nik Tools for Photoshop has included HDR tools, to allow easily combine

    the renders with different exposures to combined HDR image.

    I am really glad, that I have downloaded Nik Tools, when it was owned by Google and completely free to use.

     

    Post edited by Artini on
  • FishtalesFishtales Posts: 6,212

    The HDR in NIK Filters is to create a photographic image not a light probe image which is a different process. Yes it combines images with different exposure settings but they aren't the same as the ones to make an HDR light probe which is also a continuous panoramic dome image which is what is required to get good ambient lighting in a render.

     

  • algovincianalgovincian Posts: 2,664
    edited August 2019

    @Artini - HDR images contain light information that is outside the gamut of monitors. It must be tonemapped before being displayed. Are you sure that the Unity GPU Lightmapper isn't doing exactly that?

    - Greg

    ETA: Once tonemapped it no longer contains the same dynamic range of information.

    Post edited by algovincian on
  • algovincianalgovincian Posts: 2,664
    edited August 2019
    Mattymanx said:

    HDRIs are very good for lighting.

    For the store here at Daz, I will personally recommend:

    https://www.daz3d.com/dimensiontheory

    https://www.daz3d.com/cake-one

     

    For outside Daz3D, I would personally recommend HDRIHaven.com  I use a lot of their's now in test renders and promos.  They are very good.

    For those who dont know, you can adjust the strength of the HDRI on the Environment tab in the Render settings.  Right where you see the thumbnail for the HDRI, there is a strength setting.  I use that instead of adjusting the exposure.

     

    This is one of my latest images.  Its uses this HDRI from HDRIHaven - https://hdrihaven.com/hdri/?h=hamburg_hbf - There are 3 other versions of it on my Artstation account.  Click the banner below to go there.

    https://www.daz3d.com/gallery/images/848416/

    I've always felt that DS renders the background too light compared to how much the objects in the scene are lit when using HDRIs, and this is yet another example. I'm not sure whether it's caused by the way that materials are typically designed or what. I wish the brightness of the BG was able to be adjusted separately from the light that an HDRI provides.

    - Greg

    Post edited by algovincian on
  • MattymanxMattymanx Posts: 6,996
    edited August 2019
    algovincian said:
    Mattymanx said:

    HDRIs are very good for lighting.

    For the store here at Daz, I will personally recommend:

    https://www.daz3d.com/dimensiontheory

    https://www.daz3d.com/cake-one

     

    For outside Daz3D, I would personally recommend HDRIHaven.com  I use a lot of their's now in test renders and promos.  They are very good.

    For those who dont know, you can adjust the strength of the HDRI on the Environment tab in the Render settings.  Right where you see the thumbnail for the HDRI, there is a strength setting.  I use that instead of adjusting the exposure.

     

    This is one of my latest images.  Its uses this HDRI from HDRIHaven - https://hdrihaven.com/hdri/?h=hamburg_hbf - There are 3 other versions of it on my Artstation account.  Click the banner below to go there.

    https://www.daz3d.com/gallery/images/848416/

    I've always felt that DS renders the background too light compared to how much the objects in the scene are lit when using HDRIs, and this is yet another example. I'm not sure whether it's caused by the way that materials are typically designed or what. I wish the brightness of the BG was able to be adjusted separately from the light that an HDRI provides.

    - Greg

    I did post processing to the images, that is not the original render.  The original is darker.  I take a slight photographic approach in that I always render will a little less light since I am going to post work it to correct colors and lighitng anyways and it always easier to add light then to remove it.

     

    Go to my Artstation gallery, link in the banner below, and look at "Morning Renaissance" and "Sanctum Guardian 2" as I included the original renders as well.  You can compare the orginals with the post work.

    Post edited by Mattymanx on
  • ArtiniArtini Posts: 10,306
    Fishtales said:

    The HDR in NIK Filters is to create a photographic image not a light probe image which is a different process. Yes it combines images with different exposure settings but they aren't the same as the ones to make an HDR light probe which is also a continuous panoramic dome image which is what is required to get good ambient lighting in a render.

     

    Oh, thanks for that information. I am still newbie with all that HDRI stuff.

    Do you have any suggestions about how to combine .JPG 360 degree screenshots to HDR light probe?

     

  • ArtiniArtini Posts: 10,306
    edited August 2019
    algovincian said:

    @Artini - HDR images contain light information that is outside the gamut of monitors. It must be tonemapped before being displayed. Are you sure that the Unity GPU Lightmapper isn't doing exactly that?

    - Greg

    ETA: Once tonemapped it no longer contains the same dynamic range of information.

    Yes, I have exported 360 degrees panoramas from Unity as .EXR and they did not provided light to the scene

    like any other HDRI bought here in Daz store.

    I have previewed such .EXRs in Photoshop and they shows the image.

     

    Post edited by Artini on
  • FishtalesFishtales Posts: 6,212
    Artini said:
    Fishtales said:

    The HDR in NIK Filters is to create a photographic image not a light probe image which is a different process. Yes it combines images with different exposure settings but they aren't the same as the ones to make an HDR light probe which is also a continuous panoramic dome image which is what is required to get good ambient lighting in a render.

     

    Oh, thanks for that information. I am still newbie with all that HDRI stuff.

    Do you have any suggestions about how to combine .JPG 360 degree screenshots to HDR light probe?

     

    A .jpg wont do as it is only 16 bit whereas .exr and hdr are 32 bit. You actually need specialist equipment and software to get them right. There are some ways that they can be fudged but they aren't going to do a perfect job.

  • HoroHoro Posts: 11,343
    edited August 2019

    Artini - A true HDRI has some sort of real values, not just a one byte integers (0...255) but e.g. 15.9854 or 7,598,756.6284. So a TIF HDRI has 96 bit, 4 bytes per colour as single precision reals. EXR (or OpenEXR) uses half precision reals at 2 bytes per colour as 48 bit. HDR RGBE derives from the single precision reals (32 bit per colour) or half precision reals (16 bit per colour) the mantissa of each of the 3 colours, converts it to a byte and the exponent of the brightest colour, which also converts to a byte but only 7 bit, the 8th bit is the sign for the exponent. A saved HDR file has therefore "only" 32 bit but is expanded to a 96 bit. A JPG is an LDRI (low dynamic range image) with a 1 byte integer value per colour Oh, and HDRI files have no gamma (1), JPG and such have gamma 2.2 embedded.

    Post edited by Horo on
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