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BlueApple
09-21-2010, 08:23 AM
I'm experimenting with compositing 3D with live action environments and have some questions. I think I made my light probe correctly, but I'm not sure. Here is what I've done so far:


Shot a photo of the environment for compositing.
Placed mirror ball in the environment and shot 3 photos at different exposures (-2, 0, +2) using AEB no my Cannon.
Used Merge to HDRI on the 3 mirror ball photos into Photoshop.
Created a new scene in Layout and added an object.
Added my HDRI under Backdrop/ImageWorld.
Turned default light to 0%.
Under Compositing/Background Image I added the environment shot for compositing.
Turned on raytraced reflections, shadows, and enabled radiosity.


When I hit render my 3d elements are very dark, and aren't close to matching the brightness in the background image. If I throw kitchenProbe.hdr a lot more light fills the environment.

Did I make my HDRI incorrectly? Am I expecting too much to happen automatically? Both?

RebelHill
09-21-2010, 10:08 AM
I believe you'll find that Photoshops merge to HDR will just give u an image of extended dynamic range, within the exposure range you give it.

HDRshop on the other hand will calculate the differences between the areas in the different exposures, giving you an HDR where the brightness values run complete 0-1 (black to white). Ive always used HDRshop to do hdr creaton and it works great.

Depending on the environment in question, you may well need more shots, certainly a greater range than +- 2 stops.

bassmanjam
09-21-2010, 10:25 AM
Yeah, with only +-2 stops, you probably don't have enough dynamic range in your hdri. Check out http://www.hdrlabs.com/tutorials/index.html for more info on creating hdri images. In the meantime, I'd say crank up the intensity of your radiosity settings to throw more light into your scene.

BlueApple
09-21-2010, 11:02 AM
Thank you both for the comments and suggestions. HDRShop runs $400 (and is likely well worth it), but if I can get away with Photoshop I'm going to stick with that. I'll try taking a larger range of exposurese and running it back through Photoshop's Merge to HDRI and see if I get different results.

If problems persist I will post my source images and .hdr file and perhaps someone could investigate further.

BlueApple
09-21-2010, 11:03 AM
...and there is no Mac version of HDRShop currently.

3DGFXStudios
09-21-2010, 11:40 AM
Here you can find the information you're looking for. Also this site has a lot of useful links also for mac. http://www.hdrlabs.com/sibl/

RebelHill
09-21-2010, 12:51 PM
v2 costs... v1 is still free, and contains all u need for assembly of HDRIs, panoramic co-ord conversions, and diffuse/specular convolution.

V2 has more tools, but is generally unnessary... pairing V1 with PS gives u pretty much everything in v2.

Yes, the mac thing is a problem though... not really sure what to say about that, at least not without sounding like another smug windows user (which itself probs makes me sound like another smug windows user, dammit).

BlueApple
09-21-2010, 10:13 PM
Well, I'm investigating Mac solutions for this.

In the meantime, to RebelHill or any other smug/helpful Windows user willing to assist, here is the content I'm working with:

http://www.blueapplestudio.com/misc/3D.zip

That .zip contains my object and scene file, as well as the 3 images I used to make the hdr file via Photoshop's Merge to HDRI. If anyone with HDRshop wouldn't mind I'd love to see a comparison between the HDRI I got out of Photoshop vs. what HDRshop can produce with the same source images.

bassmanjam
09-21-2010, 11:01 PM
You might want to give Qtpfsui (that's the name) a try. Download v. 1.9.3 here. (http://qtpfsgui.sourceforge.net/?page_id=10)

I believe I have used this successfully in the past.

It takes some perseverance when trying to stick to essentially freeware. Alongside Photoshop, you should be able to do what you need. Also, if you are really interested in hdri, check out the HDRI Handbook as seen at hdrilabs. Most of the examples are even done in LW.

From my experience, precision is fairly important. There are many steps in the process and any errors can ruin your day.

rsfd
09-22-2010, 04:20 AM
as mentioned before, 3 exp. +/-2EV are by far not enough. You will most likely end up with at least 6 exp. (if you want to catch direct sun, you'll need additionally a "ND 0,6 Neutral Density" filter which reduces the light for 2EV and 9 exp.).

It's a usual way to have two Environments, when illuminating scenes with HDR images:
1. One low-res, blurred image for ImageWorld or TexturedEnvironment (depends on source images: Mirror Ball or equirectangular panoramas)
2. A second version, high-res, sharp mapped onto geometry ball around the scene for raytrace reflections

Great HDR tools for OSX (and cheaper than HDRshop) are:
the new "HDR Expose" (http://www.unifiedcolor.com/hdr-expose) from unifiedcolor
and long-time standard
Photomatix (Pro) (http://www.hdrsoft.com/index.html) from HDRsoft.
Both offer demo versions, both about $150,-
Unifiedcolor recently has released a PS-plugin "32-float" with a bit less features for $79,-

I attached a Photomatix Histogram of your hdr, you will notice how small the contrast is.

dwburman
09-22-2010, 10:57 AM
Isn't the free version of HDR SHOP limited to non-commercial use?

You could also try CrossOver to get some PC programs running on your Mac without having to install Windows

http://www.codeweavers.com/products/cxmac/

BlueApple
09-23-2010, 08:26 AM
everyone: thanks for the input; I am going to get the Handbook.

dwburman: I can't get CrossOver to install HDRshop, but I will investigate further.

bassmanjam: I am giving Qtpfsui a shot, is its merge procedure like that of Photoshop or HDRshop?

rsfd: thanks for the histogram... I will be shooting more photos. Also will be looking into those applications.

I wasn't exactly trying to pull this off for free, I just thought that between Photoshop and my camera I already spent enough money. It appears it's never enough :)

bassmanjam
09-23-2010, 09:47 AM
I am giving Qtpfsui a shot, is its merge procedure like that of Photoshop or HDRshop?

Yes, you can merge. It can also do the alignment and stitching of images to create hdri panoramas.