Making an HDRI with Gimp
kwannie
Posts: 870
Okay, I'm lost. I have been trying to create a scene of a classroom where I made an 8000 x 4000 in spherical render of just the classroom with a fixed camera. I tried to create a EXR file with a beauty canvas of the same image because I heard that is what you are supposed to do. So now the 8k image rendered and it look over exposed. If I render without doing a EXR the render looks great. If I open the 8k image that was made without the EXR in Gimp I can then export out as an HDR and open as an environmental map in DAZ and it looks like the classroom as a back ground. There is no lighting value to the image and I still have to manually light any characters I place in the scene.
As I said I'm lost. What are the real steps to creating an HDRI with Gimp? I have read that there needs to be a dark, a middle, and a light image that will be combined after tweeking the curves. What exactly is supposed to be done with the EXR image? Is it supposed to be imported into Gimp and combined with the 8k image or just for opening a canvas in DAZ with the HDR image? I just need help with this I have no clue..........lol.
Thanks!
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far as I know, and that is limited, GIMP doesn't save hdri maps properly and the lights are MUCH altered. :(
I have seen a tutorial on using Gimp for an HDR but that was just to create and nice evenly lit photo, not for use in DAZ. I have seen several comments about Gimp being able to do an HDRI but just never found the steps to do it properly. I know it has something to do with using the EXR image.
So far as I know you can't make the HDRI's used for lighting in GIMP, as you say the HDR images in GIMP are just 'improved' photos. To make HDRI's you need software that stitches together several images of different exposures, they don't have to be .exr's, jpg's work just fine. There's a free one called Bracket, it's a bit old and the UI is a bit primitive but it works. Get it here: http://user.ceng.metu.edu.tr/~akyuz/bracket/bracket.html
You then need to make several spherical renders of your scene at different exposures, 1 f-stop apart is best, 3 images works but 5 is better. save them as jpg's in a folder.
Navagate to your folder in Bracket and select all your images (hold CTRL and click on them). Then click 'Create HDR...' in the 'Process' menu.
In the dialog set the 'Exposure Variation' drop down to '1 F-stop' and click 'Create'.
From the 'Image' menu save the result as a .hdr. Don't close the window just yet.
Load the .hdr into Studio as a HDRI and do a test render with it, if the lighting or background is to light/dark go back to the image window in Bracket and open the 'Tools' menu click on the last option 'Calibrate', then click on the brightest part of you image, and ajust the Luminance value of that pixel, and re-save the .hdr. You may need a bit of trial and error to get it to look how you want.
Hope this helps.
Wow, thanks Majestic. I prefer this to having to purchase photoshop, which I continuously have to renew a license for. I hate all this leased software junk we have these days.
Don't know whether this meets your needs but I followed this video but, instead of Photoshop, I used Affinity Photo (much closer to my price range but not free) ...
Yep, I've read that here, too, and I've asked for somebody who advocates for that method from inside a DS scene to please—please—write a concise but thorough step-by-step for making it happen, including bringing the result into the DS dome map of a new scene, and showing an image of the results with it being a visible HDRI of that original DS scene that properly lights a new scene, with perhaps one character, using it.
And that request seems to be the equivalent of shouting "Fire!" in a crowded theater because the place is suddenly empty. :)
I hope you have more luck.
Thanks Marble,
To be honest prices are not what bothers me that much it is the registrattion requirements these days. These companies are always trying to get every ounce of personal information that the they can to facilitate tracking everywhere you go on the web and turn around and sell that info for others. I despise Microsoft and Google with a passion but.........what can I do about it? If I could figure out how to get a bit coin wallet and buy things that are not linked to my personal email, banking info, phone numbers or home address, I would buy or download all kinds of things like Hit Film, Photoshop, Zbrush, Marvelous Designer......................... But they all do that stupid temporary license thing. Sorry, just my little rant. I will take a look at Affinity just the same......lol.
I agree but it is the way of the world today. It is a trade-off between what you are prepared to scarifice in terms of personal privacy and what you want to make life more enjoyable. My son ignores all the Google/Microsoft/Apple intrusions and just uses the technology to the extent that it improves his daily life. I'm a bit more cautious but I'm a baby boomer and the first half of my life was writing letters on paper and making expensive phone calls from a telephone box on the street. Would I go back to those days? No. Would I prefer to keep my details private? Mostly yes.
As for Affinity. Before I retired I had access to lots of software including Photoshop. When I lost that access I tried Gimp but wasn't too happy with it but then I downloaded Affinity and it has most of the tools that I used in Photoshop for a fraction of the price. So that suited me.
Yeah, Marble I have read a lot of your posts and honestly I beleave we are on the same wavelength about a lot of things. I don't know if you are just a hobbyist like me but you usual ask the questions here that I was wanting answers to as well. I think you do animations also correct? What type of scenes do you usually try to create? I love doing entertainment scenes like night club or concert or big production like circus or vegas reveiw. Obviously the biggest draw back in DAZ is creating an authentic setting with the render considerations.
By the way is Affinity a stand alone or a renewable license platform?
Totally a hobby for me. I'm kind of odd because I never save a project when I'm finished with it - it is usually deleted within a week. I get most of my pleasure from creating and rendering the scenes and thay are all images of my fantasy world. I try to recreate scenes from my past - growing up with my family. Or from fiction I have read. I also, of course, indulge in adult fantasy from time to time and expressing that without the need to resort to watching real people in compromising or demeaning situations is another advantage of modern technology. I don't do violence, rape, guns or blood.
As for animation, I tinker with short clips. I'd love to do more but I don't have the patience to wait days for several hundred frames to render. I'd love to see my characters walking through my scenes but I'll have to wait until the render times come down significantly.
One off payment with periodic upgrades. I have not yet had to pay for an upgrade though.
If you like just creating, Id love to get your help coming up with different animation friendly stage and lighting environments I have someabsolutely amazing concert and entertainer animations thanks to Iclone motions and MMD. I'd love to be able to create like an amateur talent contest environment in a night club for a game, with animated audience, lighting and atmotsphere effects. I attached a picture below from an animation of a retro 1970's style club scene. The animation is of the girl in the vid dancing to Uptown Funk. The motion is over 8000 frames long, but I reduced all textures to about 512 X 512, removed normal and displacement maps used instances for tables chairs and lamps. and got about 4500 frames done overnight. I did image series so I can easily go back and pick up rendering again.
I respect your ambition but I think you imagine that I have more animation skills than I do. I'm a complete novice - I know a little about adding keyframes and moving poses but I have done nothing with imported animations such as Mixamo or BVH. I'd like to some day but, as I said, that will have to wait until I can render them in a reasonable time and overnight is not fast enough for me.
I do look at iClone from time to time and I'm tempted to buy it but I don't understand all the combinations of modules that they sell and how they would work with either DAZ Studio or Blender (I don't have any of the expensive packages like Maya or C4D). I've looked at game engines too but again, I am clueless about how to animate in them.
I know that I'm behind the times, but it's amazing how well Photoshop 7 still holds up. Still works with Windows 10, with some minor issues but said issues aren't noticable most of the time. The 'save for web' thingie truncates filenames if they are too long, but I can simply edit the name afterwords in the file folder.
I paid good money for Photoshop 7, but since I've been using it for almost 2 decades now, I certainly have gotten my money's worth out of it!
Kind of wishing I'd bought Photoshop CS(2?) before Adobe went to the subscription model. Sure there's Photoshop Elements, which is a much stripped down version of Photoshop. I tried using it once, but went back to Windows 7 after becomng frustrated with PE. I didn't really give PE a chance, but I'm very used to working with PS7, and old habits die hard sometimes.
Anyways, I'm all about open source getting a stronger foothold. I did try GIMP a couple of times, but again prefer my trusty old PS7... GIMP's workflow is just too 'different' to me.
I am open sorce to tj. Wish I would have gotten some of the standard tools before they went subscription.
Marble I was thinking about your ability to to put sets together, like the environments. I don't really need animation help I use BVH importing for almot all of it. I have TONS of BVH motions to work with. Let me know what you would like to do in animation and I bet I have a motion you could use. I like collaborating on artistic opinions and enjoy input from different perspectives on what elements should be in a scene. For example what is your opinion about my idea of a retro night club, like in my picture above?
Wow, I don't want to offend you by being in any way critical. I might suggest making the spotlight look more like a spotlight - with a defined outline if possible. I'd obviously have a couple of people in the audience. Maybe the fault of my display but I can't make out anything in the audience area except for the lamps. I'd possibly increse the cast of the light from them so they light up the table area a bit more. The performer needs a microphone - either on a stand or in her hand. If you are any good with atmospheric lighting, I'd add a bit of fog to make it look like a smoky room - if this is so retro, most of the audience would have been smokers as I recall. You might experiment with materials for the curtain (drapes for Americans). Mabe a satin finish? Maybe a lit neon strip on the under-edge of the stage front trim.
Coming back to the table lamps - something is wrong. They are so bright yet they don't illuminate anything. Maybe play around with IES options for them?
Marble you are not offending me at all, that is fantastic feedback. Some things are not present because it is animation, such as a fog plane or atmospheric camera. Atmospher is simply not possible for animation in DAZ at this point. Good info about the tables I can easily adjust emissive lumin on the lamps. I definately need an audience............but, render times. I am experimenting with Loretta lowrez since I can't instance character and get different poses or animation on them. This character is actually just dancing in this animation but maybe a mike on a stand would give a retro feel like you say, for a different singing animation. You think maybe a spot from the back with a wide spread angle using rectangle and very low lumins could outline the tables a bit? With the Satin I usually get a lot of noise for the amount of render time I can devote if surfaces are shiny. I do have the monochrome shaders that give a bit off gloss to them. Can I just add an IES to the bulb in the lamps, and will the IES show on the instances of the lamp? Which spot were you talking about, the one on the charater or the lights behind her? On the character I had a three light set up, you thing a single spot would look better? Thank you so much Marble, really I do appreciate your suggestions and will maybe seek more if you don't mind lending a critical eye.
Sorry, I wasn't thinking about the animation, just the scene. I usually make a kind of photo-story but the nice thing about digital is that I can slip in a short animation between a series of stills. So I set the scene in stills - with all the detail, etc., and then do a cut-down close-up for the animation using a practically empty scene. blurred background and just a smaller image resolution. By the way, I was thinkig of the spotlight which casts her shadow on the curtain. Maybe that could have a better defined circle?
This is the video that got me started making HDRIs, and I also use Affinity Photo, which currently offers a 90-day trial, and is on sale at half price.
Anyway, I just downloaded The Gimp, and it was the same procedure I described in this thread https://www.daz3d.com/forums/discussion/407891/need-some-lighting-advice, which included a link to a Gimp tutorial.
I don't use the bracketing method Thundorn describes in the video, but rather the EXR > HDR method.
Step 1: Set up the scene. Including lights! Don't light nuthin, you won't see nuthin,
Step 2: Tone mapping: Crush blacks 0, Burn highlights 1, Gamma 1 (optional in my experience)
Step 3: General render settings: Aspect ratio 2:1. Pick your size. Bigger = better, and also lots slower to render. If you don't want to see details, a smaller size should be okay.
Step 4: Set up your camera. That depends on your scene, and what your POV will be when you do your scene. For general purposes, zero out translations and rotations. Depth of Field off (your choice!). Lens - Lens distortion Spherical.
Step 5: Render Settings > Advanced > Canvasses Check canvases. Click the plus sign to get a single Beauty canvas. That should be all you need, unless you want to play with lighting.
Step 6: Render and save your render.
Step 7: Open the EXR file which will be in a folder wherever you save your renders.
Step 8: It looks like this
Step 9: Reduce exposure to taste. Something around -11 to -14. You get this. In this case Aslan Court 2, with whatever lighting came with it.
Step 10: Export as HDR.
Step 11: Select that HDR as your environment HDRI and put a sphere in the scene and it looks like this. Here the HDR is 800x400 because it's too hot to render for hours, so it looks really bad. You get something like this. Whatever lights you had, are now affecting the sphere. I'm no expert, so DOF may or may not work. ¯\_(ツ)_/¯
Actually, more like this, if you use normal gamma
Well, blow me down! He did it!
Thank you, thank you! {CLAPS! APPLAUSE!} You included the key, and usually massively missing, Step 9! (Cue the Beatles: "Number 9. Number 9. Number 9 ...)
Now if I only can figure out why my earlier attempt at a Beauty canvas came out looking like that white-on-white of yours—except where there was extremely bright sunlight in my scene, the Beauty canvas was a black smudge! I don't see how reducing exposure in PS can cause that to invert. Very weird.
Unfortunately I can't try again right now until my new computer arrives, probably Friday, but I definitely will then!
Thank you again!
Thanks again Sevrin for your amazing tips!! On step 1. you say set up the scene including lights, then you say don't light nothing. I'm kinda lost on that one, so do you mean just don't put any lights in the scene like distant lights or spot lights in the scene from the beginning? So for example if I am doing a classroom scene and I want light to come through the window to cast the window pane shadow on the wall,....Don't do that ??
I'm pretty sure he was just goofin'. The full sentence would be: "If you don't light nothin' you won't see nothin'." That's why the first part of that step says "Including lights!"
You need to add whatever lights you normally would before rendering the HDRI, or else it won't provide light. So that includes any HDRI lighting, spots,etc. You can, of course add lights to your final scene to find tune.
Sevrin, I got it to work as far as the lighting goes. The characters and the Image map look great. But...........now I need to know how you adjust the scaling of the image map. I made the HDRi of a classroom and it is gigantic compared to the charaters. If I zoom the camera in and out I can increase the size of the characters but the classroom image remains way out of scale. If try infinity with fround the image only get distorted. Any ideas what I should do?
I haven't had an issue with this, but I've not done an HDRI in a small room. Maybe this video by Sixus1 will help you. He goes over HDRI settings in great detail
In addition to the video Sevrin recommended, the two videos about HDRI maps on the first page of this thread address some of the issues you're dealing with—including specifically needed to get a character to appear as "standing on the floor" of the HDRI:
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Wow Thanks guys, This has really been a huge game changer. Sevrin that last video really cleared everything up. I'm still a bit foggy on how you use the sphere in the scene. If I put the sphere in it is visible in the render so I'm not really sure what it does. Also, is there a way to save a scene with the current HDRi and envirentment settings, so I don't have to add and tweak every time I load the saved scene?