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

Artini

Ok, thanks you both, Fishtales and Horo.

Still do not understand, what is the purpose of HDR tools in Nik Tools.

 

Artini

Fishtales said:

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.

Does it help, if I will take 360 degree screenshots with different exposures and save them as .EXR, then?

Fishtales

This explains HDR images as used in photography.

https://en.wikipedia.org/wiki/High-dynamic-range_imaging

This is what the HDR filters in NIK filters are for.

This is how to create HDR environment images.

http://blog.hdrihaven.com/how-to-create-high-quality-hdri/

Horo

Artini - you need a spherical panorama, a cylindrical won't do.

If you have Bryce, it comes with tutorials how to create a HDRI panorama from renders using 4 different methods (cube, hemispheres, mirrorball, skydome). Other rather Bryce focused HDRI stuff you find on my website under Bryce & 3D CG Documents > Mine  > IBL-HDRI, under Raytracing > IBL and HDRI, and under HDRI & Panoramas > HDRI photographic centered web-pages and a 23 page PDF how to make photographic spherical HDRI panoramas, what software and literature is available and what mistakes you can make. Just in case you want to go seriously into HDRI/IBL. How the HDRI panorama must be used to render depends on the application (Bryce, Carrara, Daz Studio 3DL, Iray), any correctly made HDRI itself works on all - but not all may be suited for a specific task.

Artini

Thanks a lot for all of the tips, Fishtales and Horo.

Yes, I have Bryce, but would like to use Unity, because it creates snapshots/rendering in real time.

I just need to go through all these documents and see, if I can use them for my purpose.

 

nomad-ads_8ecd56922e

Is there a way to create an HDRI skydome in Daz Studio and then add the relevant lighting spread into it?  I.e. if one wanted to slap a bunch of buildings into a scene to create a cityscape to later use to, say, light an apartment interior, so that they didn't have to place a bunch of buildings outside the apartment window, and so that it would give them the appropriate daylight coming in?

Hylas

^ I was just gonna ask the same question! Can I turn a DAZ scene - possibly one that has emissives - into an HDRI file?

Drip

nomad-ads_8ecd56922e said:

Is there a way to create an HDRI skydome in Daz Studio and then add the relevant lighting spread into it?  I.e. if one wanted to slap a bunch of buildings into a scene to create a cityscape to later use to, say, light an apartment interior, so that they didn't have to place a bunch of buildings outside the apartment window, and so that it would give them the appropriate daylight coming in?

 

 

Hylas said:

^ I was just gonna ask the same question! Can I turn a DAZ scene - possibly one that has emissives - into an HDRI file?

Yes, it is possible, but involves already having good lightsources (which, from my understanding, could actually be a HDRI backgrounds itself).

Next, you'd have to make a couple of 360 degree renders (we gladly have that option now, just add a camera to your scene, it is one of the properties of that camera) at different exposure values.

Finally, you need software capable of combining those seperate renders into a single HDRI file. This is the part I'm still stuck on, such software does exist, including in the shareware/freeware/opensource variety, but my searches so far for the free hobbyist variety ended up on dead links, while the professional software is often part of the package with expensive specialized photocameras or part of expensive software packages (No, I have no interest in buying the latest version of Photoshop should it have the feature, it's way out of budget for me, while my old but legal PS7 suits me perfectly fine otherwise).

algovincian

Drip said:

nomad-ads_8ecd56922e said:

Is there a way to create an HDRI skydome in Daz Studio and then add the relevant lighting spread into it?  I.e. if one wanted to slap a bunch of buildings into a scene to create a cityscape to later use to, say, light an apartment interior, so that they didn't have to place a bunch of buildings outside the apartment window, and so that it would give them the appropriate daylight coming in?

 

 

Hylas said:

^ I was just gonna ask the same question! Can I turn a DAZ scene - possibly one that has emissives - into an HDRI file?

Yes, it is possible, but involves already having good lightsources (which, from my understanding, could actually be a HDRI backgrounds itself).

Next, you'd have to make a couple of 360 degree renders (we gladly have that option now, just add a camera to your scene, it is one of the properties of that camera) at different exposure values.

Finally, you need software capable of combining those seperate renders into a single HDRI file. This is the part I'm still stuck on, such software does exist, including in the shareware/freeware/opensource variety, but my searches so far for the free hobbyist variety ended up on dead links, while the professional software is often part of the package with expensive specialized photocameras or part of expensive software packages (No, I have no interest in buying the latest version of Photoshop should it have the feature, it's way out of budget for me, while my old but legal PS7 suits me perfectly fine otherwise).

You can render a single canvas (.exr) out of DS/Iray that is both a full 360 degrees and an HDRI (containing the same dynamic range as the lighting in the scene).

- Greg

conradzoo

Hylas said:

^ I was just gonna ask the same question! Can I turn a DAZ scene - possibly one that has emissives - into an HDRI file?

Here is a nice video on how to in case you wonder.

 

- Conrad

Drip

algovincian said:

Drip said:

nomad-ads_8ecd56922e said:

Is there a way to create an HDRI skydome in Daz Studio and then add the relevant lighting spread into it?  I.e. if one wanted to slap a bunch of buildings into a scene to create a cityscape to later use to, say, light an apartment interior, so that they didn't have to place a bunch of buildings outside the apartment window, and so that it would give them the appropriate daylight coming in?

 

 

Hylas said:

^ I was just gonna ask the same question! Can I turn a DAZ scene - possibly one that has emissives - into an HDRI file?

Yes, it is possible, but involves already having good lightsources (which, from my understanding, could actually be a HDRI backgrounds itself).

Next, you'd have to make a couple of 360 degree renders (we gladly have that option now, just add a camera to your scene, it is one of the properties of that camera) at different exposure values.

Finally, you need software capable of combining those seperate renders into a single HDRI file. This is the part I'm still stuck on, such software does exist, including in the shareware/freeware/opensource variety, but my searches so far for the free hobbyist variety ended up on dead links, while the professional software is often part of the package with expensive specialized photocameras or part of expensive software packages (No, I have no interest in buying the latest version of Photoshop should it have the feature, it's way out of budget for me, while my old but legal PS7 suits me perfectly fine otherwise).

You can render a single canvas (.exr) out of DS/Iray that is both a full 360 degrees and an HDRI (containing the same dynamic range as the lighting in the scene).

- Greg

Thanks, I've been searching for posts on this subject again. There are many, but important bits seem to be all over the place (and they definitely cannot be found in the help documentation, which is about as useless as useless can possibly be on this matter)

Like, in one post it was mentioned that, for some reason, the Environment Intensity would have to be set to about 0.0002, while the EV should be set to 0, to create usable HDRI's straight out of the box. Though that could also be to compensate for some old bug that no longer applies?

Anyway, the lack of proper documentation for Daz Studio on fairly basic built-in features is extremely frustrating. There are helpful guides all over the place (forums here, deviant, some blogs and art web-sites), but a simple google turns up many dead ends and way too many links (and "helpful posters") directing to sites like HDRIhaven. (which is crap for DS, the difference in realism is just jarring, while their scenes are extremely limited in the background they provide). And the subject of just rendering your own HDRIs is generally just a remark on the side while discussing the creation of HDRIs in general or specifically from photosourced material.

Artini

conradzoo said:

Hylas said:

^ I was just gonna ask the same question! Can I turn a DAZ scene - possibly one that has emissives - into an HDRI file?

Here is a nice video on how to in case you wonder.

 

- Conrad

Great video - thanks for posting the link to it.

 

Lord Majestic

Drip said:

nomad-ads_8ecd56922e said:

Is there a way to create an HDRI skydome in Daz Studio and then add the relevant lighting spread into it?  I.e. if one wanted to slap a bunch of buildings into a scene to create a cityscape to later use to, say, light an apartment interior, so that they didn't have to place a bunch of buildings outside the apartment window, and so that it would give them the appropriate daylight coming in?

 

 

Hylas said:

^ I was just gonna ask the same question! Can I turn a DAZ scene - possibly one that has emissives - into an HDRI file?

Yes, it is possible, but involves already having good lightsources (which, from my understanding, could actually be a HDRI backgrounds itself).

Next, you'd have to make a couple of 360 degree renders (we gladly have that option now, just add a camera to your scene, it is one of the properties of that camera) at different exposure values.

Finally, you need software capable of combining those seperate renders into a single HDRI file. This is the part I'm still stuck on, such software does exist, including in the shareware/freeware/opensource variety, but my searches so far for the free hobbyist variety ended up on dead links, while the professional software is often part of the package with expensive specialized photocameras or part of expensive software packages (No, I have no interest in buying the latest version of Photoshop should it have the feature, it's way out of budget for me, while my old but legal PS7 suits me perfectly fine otherwise).

There are these 3 free HDRI creation apps:-

http://www.hdrlabs.com/picturenaut/index.html

http://user.ceng.metu.edu.tr/~akyuz/bracket/bracket.html

https://drive.google.com/file/d/0B8koCsdBHJPFSGJIb2sxdS1CMDA/edit

 

Drip

Okay, I think I succeeded at rendering my own HDRI using a canvas.

First, create an environment, and place a camera at a convenient location that gives you the desired surround view. Remember that the viewing point of the camera should be very near the viewing point for all renders you're going to make with the resulting HDRI. For wide open areas, it won't make too much of a difference, but if you make a HDRI of an interior, things just won't work out well. Set camera rotations to 0 (though it doesn't matter THAT much if you leave the Y-rotation, but it's probablly better to make a habit out of setting them all to 0.
Add an environment map if necessary, just to have a bunch of clouds and stuff if you need them, and supply your baseline lighting.

Next, go to your render settings, set exposure value to 0, and environment intensity to 0.0002 (or even as low as 0.00002 if you like things a little darker)

Also go to your camera's parameters, and set Lens Distortion type to Spherical

Now make sure all your remaining render settings (convergence, fireflies, denoise, whatever) are correct.

Finally, go to your Advanced Render Settings, tick the Canvases box, click the plus-sign right below it, and leave that on Beauty.

Hit render. Wait for the render to finish, give your render a name, and open your favourite filemanager (probably windows explorer) to find your render in its usual location. In the folder with your render, you can now also find a new subfolder with the same name as your render, and "_canvases" appended to its name. That folder contains a .exr file, which is the HDRI you just rendered.

 

Note: thanks to @PhilW for figuring out the oddities of overlighting when creating your own renders and the Exposure Value / Environment Intensity workaround.

3Diva

Drip said:

Okay, I think I succeeded at rendering my own HDRI using a canvas.

First, create an environment, and place a camera at a convenient location that gives you the desired surround view. Remember that the viewing point of the camera should be very near the viewing point for all renders you're going to make with the resulting HDRI. For wide open areas, it won't make too much of a difference, but if you make a HDRI of an interior, things just won't work out well. Set camera rotations to 0 (though it doesn't matter THAT much if you leave the Y-rotation, but it's probablly better to make a habit out of setting them all to 0.
Add an environment map if necessary, just to have a bunch of clouds and stuff if you need them, and supply your baseline lighting.

Next, go to your render settings, set exposure value to 0, and environment intensity to 0.0002 (or even as low as 0.00002 if you like things a little darker)

Also go to your camera's parameters, and set Lens Distortion type to Spherical

Now make sure all your remaining render settings (convergence, fireflies, denoise, whatever) are correct.

Finally, go to your Advanced Render Settings, tick the Canvases box, click the plus-sign right below it, and leave that on Beauty.

Hit render. Wait for the render to finish, give your render a name, and open your favourite filemanager (probably windows explorer) to find your render in its usual location. In the folder with your render, you can now also find a new subfolder with the same name as your render, and "_canvases" appended to its name. That folder contains a .exr file, which is the HDRI you just rendered.

 

Note: thanks to @PhilW for figuring out the oddities of overlighting when creating your own renders and the Exposure Value / Environment Intensity workaround.

Wow! That works pretty well! Thank you! I recommend setting the dimensions to 10000x5000. The HDRIs take quite some time to render, but if it's an environment you know you'll be rendering with repeatedly it's probably worth the time - since it SHOULD make the renders later with the HDRI quite a bit faster. 

I think even at 10000x5000 it might not be big enough for the HDRI environment to be sharp and clear in renders, so what might be more advantageous is to set the dimensions smaller for faster render times and then use DOF with the camera. In that case, you could also use denoiser too which should speed up render times. One might even be able to render the HDRIs with DOF on the spherical lens camera. 

This is a really cool idea, thank you, Drip and @PhilW ! I rendered a couple of HDRIs this way to experiment and it seems to work ok. Again though the render times are pretty high for the HDRIs and once you load them onto the scene they are not really "sharp", so I think a DOF camera would probably work best with this specific type of HDRI creations.