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View Full Version : Suzanne goes to the Beach (HDRI Test)


Apollux
01-01-2006, 06:22 AM
This is my first ever serious attemp to use Yafray, with my first ever HDRI illuminated image, with also my first ever HDRI Light probe.

http://apollux-designs.com/3dcgi/Tutorials/LightProbe_Making/BeachSuzane_Small.jpg

Full size version is available at http://apollux-designs.com/3dcgi/Tutorials/LightProbe_Making/BeachSuzane.jpg

Yesterday (Dec 31th) my family decided to spend the last day of the year at the beach.. And since Im already doing research for a BlenderArt article about Image Based Lighting, I took my tripods, mirrror balls and camera to the beach as well.

This is the Light Probe I came up with
http://apollux-designs.com/3dcgi/Tutorials/LightProbe_Making/PalenqueHDR.jpg
(LDRI version, of course. The real one is 1024 x 1024)

Ill try to clone out the tripod, but other than that I think it came up prety well for been my first attemp.

BTW, HAPPY NEW YEAR !!

Samo
01-01-2006, 09:03 AM
The monkey's specular reflection is in the wrong side. Should be at the opposite one.
The horizon reflected is Suzzanne's face should be at the same height than the horizon on the photograph.
Apollux, lighting and compositing is the art of observation.:thumbsup:
Good luck with these tests.

Inktvlek
01-01-2006, 10:52 AM
I don't think anything's wrong with the specular (check the waves, they have the specular at the same side), but you're probably right about the horizon. Apollux, you can fix this by pressing the "real" button (which should be enabled by default IMO).

Nice one anyway! Where did you buy your shiny balls? Will you share the hdr with us eventually?

Apollux
01-01-2006, 11:57 AM
Thanks for the advices guys. Ill post an update after I find a way to clone out the tripod. Do you know of any free and/or opensource 2D editor that supports HDR files? I know of Cinepaint, HCR-Edit, Pixel Image Editor, and Cinelerra (not precisely a 2D editor)... are they any more you know about? I need more, specially for Windows

Nice one anyway! Where did you buy your shiny balls? Will you share the hdr with us eventually?

Of course, Im hoping that by the time the article comes out to have a gallery of HDRI probes to share.

I got the mirror balls at a bearings store (yes, they are stores that speciallize on bearings). And they were (to my own surprize) quite unexpensive. In fact, some of them where literaly for free.

Santo Domingo city isnt that big so I wasnt hoping to find a big choice of bearing sellers.. I was quite wrong, they have a WHOLE section of the phone book just for them. I spent one entire day visiting bearing stores and I just scrached the surface.

Inktvlek
01-01-2006, 12:58 PM
What size did you settle for eventually? A while ago I visited this DIY shop, and they had some bearings on display and I asked what they cost... because of the precision they were priced from 40-100 (and up!) (this equals 35-120 USD). The biggest ones were still quite small though (about 25mm, 1 inch).

Apollux
01-01-2006, 01:08 PM
The one I used for the beach probe is 2.25 inches in diameter and I got it for about 40 US dollars.

I dont want to let much details out yet, but here is a little factoid: The smaller the ball the better the result. Of course, the smaller the ball the more powerfull your zooming lenses has to be.

If I had the camera of my dreams, I would use a ball that is only 1 centimeter or less in diameter.

Apollux
01-01-2006, 01:14 PM
BTW, does anybody knows of a .HDR <-> .EXR converter ?

Blender already supports .HDR, but since EXR support is comming soon, I would like to have my probes in both formats.

Samo
01-01-2006, 03:40 PM
I don't think anything's wrong with the specular (check the waves...

Nope. Where the sunlight is coming from in that photo?:bounce:

Inktvlek
01-01-2006, 05:53 PM
If you check the probe, you'll see that the sun is at the left of the beach... I think you need to do weird tricks to make the highlight appear at the wrong place when you use the background image as a lighting source (i.e. most likely there's NO lamps in his scene!)

Apollux
01-01-2006, 07:39 PM
The pictures for the probe were taken at around 11:00 am. The time of the day and the Longitude/Latitude of the place where they were taken are causing the sun to shift from the center.

Had those images been taken over the equator line, at exactly midday, then the sun would be at the real center.

But Samo has a good point (and a good eye). The probe was made at 11:00 am, but the background picture was taken around 1:00 pm.

And no, there are no lamps on the scene.

shadowman99
01-01-2006, 07:44 PM
I have a 14 inch mirror "gazing ball" that I picked up from a gardening store. It's metal and shatter proof. It cost me 12 bucks. You might find something like it at a local gardening or home improvement store. They're pretty handy.

Blikkie
01-01-2006, 08:37 PM
Wouldn't balls from a Christmas tree (that just have ben sent to the attic again) work out quite nicely? They are not perfectly round, but I wouldn't expect minor flaws to be that much of a problem. You'd have to package them very carefully thou...

Samo
01-01-2006, 08:41 PM
Balls:
http://www.dube.com/

Inktvlek
01-01-2006, 08:48 PM
But Samo has a good point (and a good eye). The probe was made at 11:00 am, but the background picture was taken around 1:00 pm.
So at 1pm the sun would be at the opposite site? That's extremely fast, since in your probe the sun is still quite low. I can't say anything serious about that though, since I have not been anywhere even near the Dominican Republic and don't know how a day in December is like.

Anyhow, I thought the background we were seeing was the same image as used for the IBL. I guess at a resolution of 1024x1024 for the complete world, that would be a bit blurry though. I have some more questions, but I'll wait until the article is out.

Inktvlek
01-01-2006, 08:51 PM
Balls:
http://www.dube.com/
Cool, they sell Chinese Therapy Balls without bells :o)

Diameters and Weights:
55 MM (2.17 IN.)198 GM (7 OZ);
63 MM (2.50 IN.)312 GM (11 OZ);
73 MM (2.875 IN.)368 GM (13 OZ).

#0484 55 MM Steel Ball $8.00 ea.
#0485 63 MM Steel Ball $15.00 ea.
#0486 73 MM Steel Ball $18.00 ea.

nice price too!

Apollux
01-01-2006, 09:09 PM
Wouldn't balls from a Christmas tree (that just have ben sent to the attic again) work out quite nicely? They are not perfectly round, but I wouldn't expect minor flaws to be that much of a problem. You'd have to package them very carefully thou...

Here is your answer: http://www.andrew-whitehurst.net/hdri_tut.html
In other words, yes, they can be used.

Apollux
01-01-2006, 09:15 PM
So at 1pm the sun would be at the opposite site? That's extremely fast, since in your probe the sun is still quite low. I can't say anything serious about that though, since I have not been anywhere even near the Dominican Republic and don't know how a day in December is like.


Hmm.. in 3 hours the sun position changes quite a lot, but mostly is my fault. Remember that I was working on the sand. Turns out that it is QUITE DIFICULT to get two tripods to stand totally vertically and at exactly the same height when you are working on sand... everytime you touch the camera's tripod it sunks a little :rolleyes:

Apollux
01-01-2006, 11:35 PM
Does anybody have links to tutorials dealing with HDRI + Blender? or HDRI + Yafray ?

So far Ive only been able to find the Biorust one. But for the most part the info posted on this forum have proved far more valuable.

RyanVII
01-02-2006, 04:29 AM
Did you setup any lights? Or is this completely lit off the HDRI Image?

Inktvlek
01-02-2006, 09:53 AM
About tutorials... There's not much to it, I guess. I would NOT recommend the BioRUST tutorial at all! Don't even consider giving that link to your readers, since it misses all the most important information. First of all, it uses the HDRI just for reflections and it fakes the soft shadows with a spot (you'd expect them to show how to actually light your scene with an HDR image). Secondly, it lacks all the important mapping settings (angular, hori), making it pretty much useless!
I did a tutorial for solidworks users to render their stuff in blender + yafray, it's on the wiki (http://mediawiki.blender.org/index.php/Tutorials/Import_and_Render_a_SolidWorks_Model#Creating_an_HDRI_environment). That tutorial has a small part about HDRI. It's short but it contains all the necessary info! Feel free to port just that part to a new page and make it a bit more elaborate.

edit: I copied that part to a new page and added a few lines. You can modify or add (I think it needs a picture of a nice shiny ball/suzanne) stuff. Just make sure you have read the style guide (http://mediawiki.blender.org/index.php/Meta/Style_Guide). If you upload a file, make sure you name it according to the naming scheme mentioned there.

the page is here: HDRI with YafRay (http://mediawiki.blender.org/index.php/Tutorials/HDRI_with_YafRay)

If you don't have edit rights yet, then pop into #blenderwiki on irc.freenode.net and talk to S68, Spiderworm or me.

Apollux
01-02-2006, 10:58 AM
Thanks for the info. What I have in mind is far more ellaborated than a single page, but you got to start somewhere :D (Just PM you the TOC for the article/tutorial).

BTW, you missed the "EmitPwr" and "GI Pwr" settings that are so needed to fine tune the rendering.

:wavey:

Inktvlek
01-02-2006, 12:23 PM
Heh, this wasn't meant as a replacement for your article, just a quick yafray + hdri guide (although a bit too quick now).

The TOC looks nice, a very good guide for understanding the principles of IBL.

I know about GI power and Emit Power, but in the tutorial it was taken from was just a small part. The goal of that how-to was just to show the workflow, not an in-depth explanation of all the settings needed (although I would not mind at all if it was made a bit more clear about some things).

I could not find a user by the name of "Apollux", so I could not grant you edit rights yet.

Apollux
01-03-2006, 03:52 PM
I just created my account on the Wiki.

Answering what you asked on the PM:

I originally started to write the article as part of a bach of new contents for my website. Then I was approached by the guys that run the BlenderArt Magazine. Seems that Issue #3 will be about rendering, so the article kind of fit with the subject.

I already talked to them and they said that they are OK with the article appearing in other places, even if they appear before Issue #3 is out.

What I have in mind will be about 10 to 15 pages long.. I guess I fits well in the Wiki, and maybe into the Manual.. I understand that the CJ aims for shorter articles... but I would need to finish the article and contact the guys that run the CJ to see if they are interested and if we would need to re-edit it on a shorter form for the CJ.

Inktvlek
01-03-2006, 04:30 PM
I just gave you edit rights. If you want to start writing the tutorial/article in the wiki, this is probably the best place/name: http://mediawiki.blender.org/index.php/Tutorials/Image Based Lighting
You will need to decide if it will be one big page, or if you make a general introduction at "Tutorials/Image Based Lighting" and add sections further down that directory ("Tutorials/Image Based Lighting/What do you need", "Tutorials/Image Based Lighting/HDRI Light Probe Making" etc.). Don't make the sections too small.

the nice thing about having it in the wiki, is that once Blender supports IBL aswell, a section about that can be added aswell.

Apollux
01-03-2006, 07:26 PM
the nice thing about having it in the wiki, is that once Blender supports IBL aswell, a section about that can be added aswell. According to Paul Debevec (you know WHO is he, dont you?) Blender already supports IBL since at least 2002. http://www.debevec.org/CGAIBL2/ibl-tutorial-cga2002.pdf

Ill finish writing the article in the format Im currently working (each section one page) and them will transfer all to Wiki).

Apollux
01-04-2006, 02:16 AM
For those interested, Part 1 of the article is ready. http://apollux-designs.com/3dcgi/3dcgi.php

Any feedback/correction would be much appreciated.

Inktvlek
01-04-2006, 09:16 AM
According to Paul Debevec (you know WHO is he, dont you?) Blender already supports IBL since at least 2002. http://www.debevec.org/CGAIBL2/ibl-tutorial-cga2002.pdf
Hehe, well the mighty Paul must have been mixing up YafRay & Blender then, since my build clearly doesn't (if it does, explain me your magic trick!)

For those interested, Part 1 of the article is ready. http://apollux-designs.com/3dcgi/3dcgi.php

Any feedback/correction would be much appreciated.

well, all I could find was some spelling/grammar errors, maybe some repetitive sentences too... But these can be easily fixed once the article is done. The main point is very clear. To improve readablitity a bit more you could remove some whitespace, right now you have paragraphs that only consist of one sentence, which makes it harder to scan through.

I would mention though (for a more thorough understanding) that monitors are unable to display HDR images.

Samo
01-04-2006, 10:37 AM
useful links, I hope:
http://www.rendermania.com/HDRI/index.shtml

Apollux
01-06-2006, 04:57 AM
Part II at http://apollux-designs.com/3dcgi/Tutorials/IBL/LightProbeExplained.php

Part 2 isnt finished yet, but it is already usefull. Time to sleep now, Ill finish it tomorrow (hopefully).

Apollux
01-07-2006, 08:26 PM
Part II is ready, and as before would appreciate your feeback.

(all the suggestions will be applied once the 4 parts are ready)

BTW, changed a little bit the site front page, as it was displaying wrong in some screens.

Inktvlek
01-08-2006, 10:37 AM
Nice to see the progression, Apollux!
I have some remarks:
The article seems loaded with a lot of technical terms. Ofcourse, that's partly because of the nature of the article, but sometimes it looks like the terms really don't add anything. Especially the names of the projection methods sound far too complicated for the matter they represent > I think the pictures alone speak for themselves and the readers are not really interested in what they are exactly. I would put all those informational links gathered at the end of the article in a "further reading" paragraph, named & ordered by theme.
Which brings me to the second point, you use links differently throughout the article without an obvious reason. Sometimes they're bold, but then not all bold words are links > how should I know? Then there's normal coloured links, which makes more sense. Also, as for readability, you have a lot of bold words, which makes reading a bit harder. Everytime I reach such a bold word, my eyes stop for a moment, not always necessary.

Then there's again some grammar/spelling errors, but I won't list them all here. If you want I can do a spellcheck when you're done (preferably in the wiki).

Most importantly: this is a great gathering of information about the subject, very usefull and you succeed very well in getting the point accross. Rock on dude! :buttrock:

Apollux
01-09-2006, 07:32 PM
Hey Inktvlek, thanks for the remarks.

I put that much enfasis on the projection methods because on Part III the reader will actually USE THEM, not just know their name but really use them to fix the probe's distortions, very specially the Mercator Projector.

I agree, the use of bolds seems a little bit random, Ill see what I can do about it. Likewise for the links signaling.

About the grammar/spelling errors, I would really appreaciate any corrections you could do, specially now before I make the link public outside the Blender forum... English isnt my native language, so any help on that regard would be appreciated.

Parts 1 and 2 are pretty much done now, so if you could point out any mistakes now, so that I could have the grammar for the entire article neat and sound by the time Part 4 is done, that would be wonderfull.

Apollux
01-09-2006, 07:39 PM
I would put all those informational links gathered at the end of the article in a "further reading" paragraph, named & ordered by theme.While doing the research for this article I garthered about 100 links related to IBL and HDRI. Those links that are very specific to one particular subject Ive been presenting them along their subject, but I got a few selected "juicy" links that will be presented on a "further reading" section at the end.

For example, Brock J. Stearn graduation Thesis is entirely about IBL, and I got a link to the full copy. That link goes into the "further readings" section.

Inktvlek
01-09-2006, 08:57 PM
I sent you a reviewed version by email!

Apollux
01-10-2006, 04:07 PM
Thanks Man !!

Most of those changes will make into the final version :thumbsup: I tryed to implement a less visual agressive format for part III, is it any better now?

As before, here is the work-in-progress Part III
http://apollux-designs.com/3dcgi/Tutorials/IBL/LightProbeMaking.php

If you have any experiences with the software tools mentioned, then I would like to hear about it :)

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