Creating HDRI Maps for Blender

[jruzic]

Is anyone here familiar with the process of creating HDRi maps in Affinity Photo for 3d modeling? I am struggling to find info on the correct process. I did find some documentation from Affinity, but there was just not very much info on it and I still am a bit confused on how to correctly set this up. Thanks to anyone that can throw me a video or more detailed explanation!

 

Best,

Jordan

[NotMyFault]

@James Ritson

[James Ritson]

On 4/18/2021 at 4:08 AM, jruzic said:

Is anyone here familiar with the process of creating HDRi maps in Affinity Photo for 3d modeling? I am struggling to find info on the correct process. I did find some documentation from Affinity, but there was just not very much info on it and I still am a bit confused on how to correctly set this up. Thanks to anyone that can throw me a video or more detailed explanation!

 

Best,

Jordan

Hey @jruzic, it depends on what you're referring to with the creation process really. Affinity Photo cannot stitch a series of images into a 360 equirectangular image (you would want Hugin or PTGui for that), but it can HDR merge and retouch in 32-bit linear unbounded colour format.

For example, have you taken a series of bracketed exposures with a 360 camera? If so:

1. Use File>New HDR Merge and add your images. Uncheck "Tone map HDR image" and possibly choose not to align images either (since this may crop the image slightly which you need to avoid for a full 2:1 ratio 360 image)
2. Once it has completed, you will be presented with your unmapped 360 image with no tone mapping
3. At this point, you can retouch the image if required using various tools like the Inpainting Brush Tool. You can enter live projection via Layer>Live Projection>Equirectangular Projection which makes it easier to edit in perspective. Don't forget to remove the projection once you've finished editing.
4. You can also change the base exposure of the HDRI by adding an Exposure adjustment. This won't clip any bright tones above the 0-1 range so don't worry about this.
5. Now use File>Export and choose OpenEXR or Radiance HDR for your export format. You can reduce file size with EXR by choosing the half-float preset, which will encode to 16-bit half float rather than 32-bit. For most HDRIs the loss in precision is negligible.
6. Then load that HDRI into blender with the usual methods (World surface texture etc).

If you're not working with 360 imagery, you can also apply the above method to standard bracketed photography (don't tone map the image) and export it as EXR/HDR. Then in blender you can load this HDRI as an emission texture onto a plane or something similar, which will use it to illuminate your scene.

PS if you need to stitch the 360 image initially and decide to use Hugin/PTGui or another app, don't forget to save it out as a linear unbounded 32-bit or 16-bit format. They will probably provide a TIFF output for this, or OpenEXR. You can load this into Photo and do any retouching work, then export back out to EXR/HDR.

Hope that helps!

[CyberZorg]

Hello,

I'm trying to create HDRI images in order to use them as "Texture Environment" in Blender.
For this I use a "GoPro Fusion 360" driven by an Android app called "Bracketing for GoPro Hero".
I take 5 photos (-2 / -1 / 0 / +1 / +2)

I overlay the JPGs in Affinity following the recommendations that @James Ritson offers above, but I get a dull HDR image, worse than the EV 0 image and when I use it in Blender there is no brightness information (for casting shadows).

Can you help me find where I am making a mistake?
If you want I can provide the jpg images by WeTransfer for analysis.
Thanks.

[NotMyFault]

2 hours ago, CyberZorg said:

Hello,

I'm trying to create HDRI images in order to use them as "Texture Environment" in Blender.
For this I use a "GoPro Fusion 360" driven by an Android app called "Bracketing for GoPro Hero".
I take 5 photos (-2 / -1 / 0 / +1 / +2)

I overlay the JPGs in Affinity following the recommendations that @James Ritson offers above, but I get a dull HDR image, worse than the EV 0 image and when I use it in Blender there is no brightness information (for casting shadows).

Can you help me find where I am making a mistake?
If you want I can provide the jpg images by WeTransfer for analysis.
Thanks.

Hi, can you upload the images directly in the forum (no wetransfer) ?

If the image looks dull, did you raised exposure or applied a curves adjustment ?

Can you upload a screenshot of how the rendering looks in Affinity, including the histogram, set max to 2 or 4?
 

[CyberZorg]

Hi NotMyFault, thank you for your reply.

Each of the 5 equirectangular photos is 5760x2880 pixels and 18MB, which is 90MB, isn't that beyond the forum restrictions?
(That's why I suggested WeTransfer)

The images are dull without me applying any effects.

I have attached a screenshot to this post as you requested.

Thanks.

[CyberZorg]

Ok, I just saw that I am entitled to post 2 GB
Here are the original bracketed photos:

[CyberZorg]

And here is the HDR photo I get:

HDRI_Foret.hdr

[NotMyFault]

Thanks for uploading.

The image looks dull because there actually isn’t much (usable) DR. The sun is still totally overexposed / blown out even in the “darkest” exposure, you would need much darker exposures e.g. -10 or more. For sun capture with a 600mm tele zoom, I use a ND 1000 plus ND8 or ND64 filter and 1/1000 or less exposure, to have a chance to see e.g. dark spots and surface structures. 
The rest of the scene has relatively low DR because it is all shaded / soft ambient light by the trees, so there are no deep dark / black tones.

You could artificially stretch the tones, but this could look totally unnatural. 
A scene where half of the area is lighted by bright sun, and half of the area is in shadows, but showing the same object, would produce more usable DR.

Maybe the camera software is doing too much processing, a RAW image might provide better results.

 

[CyberZorg]

Thank you for your detailed explanations which allow me to better understand where the problem comes from.

Unfortunately the GoPro Fusion can only vary its exposure from EV-2 to EV+2 and it is not possible to adapt ND filters to it.

Too bad, I had hoped to be able to create basic HDRI images with this GoPro Fusion.

[summer1]

Coming back on creationg HDR :

 

It's the first time, I'm using Affinty for merging HDR.

when I use the setting with option "suppress ghost" " or "align auto", I have a nice HDR but the size is not good ratio (2 for 1) as you explain.

If i remove, these options, the size is good, but the HDR is black (like only one picture is used) => seems to have a big bug here ?