HDRI Creation
Hrafnhild
Posts: 4
I love the HDRI lighting and backgrounds.
Is there a way to create a 360 degree HDRI image in one of the programs that creates scenic vistas like Carrara or Bryce that could then be used in Daz Studio for both background and lighting? Whenever I try to do a search for how to create HDRI I get photography and Photoshop tutorials and tutorials for using them in various 3D programs for background and lighting but nothing on how to create them with 3D. If it can be done with a real camera perhaps it can be done with virtual ones.
It would be nice to create a complex scene with fantasy city architecture, sky and terrain that pushes the machines limits then use that as a background environment.
Has anyone else explored this?
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I believe that this is how Flipmode creates their Easy Environments (High Peaks, Green Hills...etc). But, I don't know the particulars for the render.
I believe you can do it in Vue, but I wouldn't know how it's accomplished.
Laurie
Search for cubemap or spherical camera.
I wondered that to but it looks daunting if one does not have the gear.. I been buying them up I get cool results blending them with content. Be nice to get freebies that work properly..
A spherical camera will get you that 360° render but it won't get you the HDR part. You would need to see if the software can render in 32-bit color. Normal photos and renders are done in 8-bit color. The good HDRI domes that I have purchased are done with the (High Dynamic Range) of 32-bit color. This makes the brightest parts of the photo/render even brighter and the darker parts even darker. This creates much more accurate lighting.
Say for instance, you take a spherical photo on a cloudy day. The sun is behind a cloud but the entire sky appears to be somewhat evenly lit. With a 32-bit camera, you can capture that the sun is still brighter than the rest of the sky so the sun's direction can still be seen in the resulting render.
A good example would the products by DimensionTheory. Let's take this one as an example: https://www.daz3d.com/iradiance-hdri-variety-pack-one
The texture files are saved with an .HDR extension. When I open them up in Photoshop, it says it has 32-bit color. DimensionTheory must have access to a really nice camera.
As an experiment once, I took and old dome texture from 3Delight. I wasn't getting great lighting from it in iRay. So I converted the texture to 32-bit in Photoshop and then increased the contrast. You couldn't tell by looking at the texture but the lighting back in Daz was much better and had more contrast.
It isn't quite as simple as taking a 32 bit 360º image. HDRI's are made up of a series of images starting at the darkest and finishing at the lightest, there could be many images the more the better, and then they are combined into one 32 bit image which then has all the lighting information in it so that it can be used for lighting. Just about any 32 bit 360º image can be used as an HDRI but it wont be very good at lighting the scene. HDRI to me is wrong for what a lighting image should be called, it is really an HDRLI, High Dynamic Range Light Image.
I noticed that often HDRI lighting gives a light too much colored (I think mainly when the gap between light from sun and light from othe part of the image is not big enough). For example, in real life, sky doesn't make us blue. I think it can be better to use at least two HDRI, one with normal colors for environnement and background, anoter one (the same) less saturated and with mainly the color of natural light for lighting, or to use anoter light as sun correcting the dominant color of the HDRI.
Terragen is used for creating skys, mountains and landscapes. It can export HDRI images, with all the high-dynamic lighting stuff.
https://planetside.co.uk/free-downloads/
btw, if you're searching for HDR files on the Internet, and the image is saved as HDR or EXR, then it's most likely to be a high-dynamic image. If it's saved as JPG,PNG or anything else like that, then absolutely not.
An HDRI can be made (faked) from a Bryce render. It can be used in Studio/Iray. However, Studio/Iray handle HDRI differently, ambient light can be quite fine, the main light source often does not provide enough light. I have a 3-part video on the subject of faking an HDRI from a Bryce render, the link is on my website (3D CG Documents > Videos > Horo > More Videos 9, 10, 11). Sometimes, a spherical LDRI panorama mapped on a sphere and put the camera inside may be already good for Studio. There are several ways to make a panoramic render, an additional program is usually needed but there is also the Spherical Mapper to rendeer a spherical panorama up to 4000 x 2000 pixels.
HDRI Labs ( http://hdrlabs.com/news/index.php ) is your best source for anything to do with HDR images. He has links to software and tutorials. I used my ordinary Nikon (an older D3X) camera and a regular lens to make a ton of HDRI's while working in the Mojave Desert and Death Valley last year. PtGui worked wonders.
Multiple images are used when building an HDRI from photos because of the limits of the hardware, if you are handling pure data from render to HDRI (and if the engine is actually working at full 32 bit precision) then there's no virtue to using multiple images for the sake of it as far as I am aware. Of course if the render engine is producing 32 bit end images but without using the full range of values in generating the image then that is not true.
A single image only has the light values set in the camera at the time the image was taken. To get a true HDRI that will light the scene properly then a series of images has to be taken and then combined into the final 32 bit image. There can be images from a few stops up or down to as many as the photographer decides to take. Only in this way will a full range of light from the deepest black to the brightest white be available in the final image to produce believable light in a render. Some HDRI that are available may be just as you have described, a single 32 bit image, others might have six or eight stops of a difference in the finished image, the best could have as much as 18 stops of a difference. The range of light from all of these will be different and will light a scene differently.
Yes, with photos - but the discussion is of software rendering, not physical cameras.
You can combine different render exposures with Photomatix to get HDR. I wrote a tutorial some time ago, here: https://www.daz3d.com/forums/discussion/136101/diy-iray-hdri-using-daz-studio-renders#latest
No, the discussion is about making an HDRI for lighting, the same principal applies to get a high dynamic range image that has enough information in it to make that possible. Just producing a 32 bit spherical image in the software will give you some light but any image will do that to a certain extent. To get the full dynamic range you have to render images at different settings to get the full range from black to white and then combine them with software that can take the images and produce a 32 bit HDR or .exr file.
This was discussed here before and I put up some links.
https://www.daz3d.com/forums/discussion/comment/899460/#Comment_899460
Hello!
Maybe someone already used (and probably certainly is) with this product for lighting - "iRadiance - HDR Mesh Lights for Iray". I need to render a panoramic interior 360-degrees, lighting it before it. However, when I use this preset, the light sources themselves (lamps of various technical forms) can not be hidden and they are visible on the final render as part of the interior. I do not know how to solve this issue. Maybe someone already used this product?
You can do it in Carrara - there are a couple of ways that I know of.
The Expensive But Easy Way - buy Octane Render for Carrara, render with the Spherical Camera and save the render as an HDRI. It actually saves as an EXR but you can load this into Photoshop and then save it out as an HDR with no loss of quality. Easy!
The Cheaper But More Difficult Way - you need to render a series of images with Carrara's Spherical camera which mimic the effects of different exposure levels in an actual camera. Unfortunately Carrara does not have an exposure control, so you have to do this manually. Also you need to make sure that light sources are visible when rendered - with normal lights, you can see the effects of the light but you can't see the light itself, so you either have to add something like Lens Flare or you have to put something like a plane behind the light so you can see the effect. Then produce a series of images, halving the brightness of all the lights for each pass. Finally you have to put these into something like the Photoshop HDRI maker to compile the HDRI. And don't be too surprised if not every attempt at this works, as you are dealing with a virtual world and not the real world, so it may not compute the same as a real set of exposure images.
I hope this helps. I can recommend Octane more generally, but there is no getting away that it is not a cheap option.
P.S. This may be possible with Luxus and Luxrender too - not 100% sure.
PhilW, thank you so much! I was very interested in the option using "Octane Render for Carrara". Could you write a link to this product, please? Tried to find, but has not yet found. In particular, is it possible to use "DAZ 3D" for work, or in this case it is required to install Carrara-program?
https://home.otoy.com/render/octane-render/purchase/
This is the Octane store on the Otoy site - if you have a look at the list of Plugins, you will see that Daz Studio is listed in addition to Carrara (and many others). I only have the Carrara version as until recently I was using Carrara almost exclusively, but I have started to dabble into Daz Studio (as today's released products will testify!). You need both the standalone and a host to really have a workable solution (you could export from your host, import into Octane Standalone and then have to redo all the shaders, but I'm pretty sure you'd tire of that very quickly!).
DAZ Studio Iray had a spherical camera added in 4.9. I'm not sure if you can use the Canvases feature to get the exr with the correct lighting data built in.
It's not cost that stops me, but the fact that I do not want to change the choice of software - that is, I would like not to change "Daz Studio" to "Carrara".
Here is a more or less successful rendering, which I covered with the use of 46 objects of this product - Iray Ghost Light Kit. It was quite cumbersome. Maybe you could advise any other lighting that is compatible with the Iray?
You can use HDRIs with iRay and they can give great results - I know that sounds odd as you are trying to create an HDRI, but if you have a room as in your example, you will then create a different HDRI by including the objects in your scene. There is a Sun/Sky system which you can you, or you can use mesh lights (which are just objects, quite often simple planes, which have emission turned on in the Shader). I would tend to avoid the Ghost Lights when trying to create an HDRI, as these produce light but they don't show themselves in the scene - you actually want lights that ARE seen, as they will then be incorporated into the HDRI image. If they are not visible, they won't be.
Sorry, nothing from me at the moment - I have produced some HDRIs which I have used myself but they are not part of a product at the moment.
Unless I am misunderstanding you, you are wrong here. If your render output is a 32bit HDR or EXR (which many render engines are capable of doing, including Octane, Cycles, and Iray) it contains all the same lighting information as if you had rendered multiple images and combined them
The only caveats with this are if you used any lights in your scene with no visible meshes in the render (like the distant light in DS) those will obviously not be captured in the image and so be missing from the hdr
An easy way to test this for yourself is set up the Iray sun-sky to have crisp shadows, render out a a panorama with a canvas to get the exr, and then compare this with the original sun-sky. There should be no difference in terms of lighting.
There is a way to find out if the 3D rendered .exr is the same as a photo generated one. Put them into a 32 bit viewer and turn the brightness down as far as it will go. If the lightest parts disappear then they aren't going to give the intended lighting in the scene. Any image used as IBL should always have some light in the brightest part of the image.
j cade - I doubt that a render saved as OpenEXR or HDR contains the full dynamic range. As Fishtales says, check it in a HDRI capable program. If the program really does output the full dynamic range, than it must render the scene as 32/96 bit. With 8/24 bit shaders and gamma applied that would be very difficult. I've photographed hundreds of HDRI panoramas and also faked quite a few from renders. Bryce renders 16/48 bit internally and can also export 32/96 bit TIFF and HDR, but the dynamic range is still limited. I need at least 4 renders with different light settings to be able to fake an HDRI that also has a dynamic range of an HDRI - or at least of a DRI.
So inspired by Horo's post, I decided to test it out. I rendered an image with a couple of different coloured mesh lights in Octane (for Carrara, but any host should give similar results). I then placed a spherical camera where the figure is, hid the figure and rendered a spherical EXR with no tone mapping which I then converted to an HDR, so that I could then delete the mesh lights and replace them with the generated HDRI. Adjusting for intensity, it gives a very similar result, certainly not lacking in dynamic range. The differences may arise because a mesh light has a finite distance, and therefore the angle of incidence of the light will be very slightly different at different points on the model, whereas with an HDRI, the lights are effectively at an infinite distance and therefore the angle of illumination is the same across the whole model. Other than that, I think they are pretty much the same.
Mesh Lights:
HDRI Lighting:
I think it is showing the bump a bit more (rather than it being noise) due to the changes in the incidence angle of the light, that's the kind of thing that I meant before. Also there is more shine on the lips. But it had been said that a directly rendered HDRI would not be able to capture the full intensity of light and that is not true here. Any differences are not due to lack of brightness, the overall intensity looks pretty much the same to my eyes.