Real FX Studios GlassWorks (tm) Caustic Sampler Tutorial

[Prince]

[size=6]Real FX Studios GlassWorks[/size][size=2](tm)[/size][size=6]Caustic Sampler Tutorial[/size]

This is the unofficial "Caustics Sampler tutuorial" which has been so requested by a recent poll. I would be honored if the staff of the
elysiun community would post this as a sticky for future reference (and if need be post it in the General section). Many thanks to the blender developers, yafray developers, and blender community participants for there support and inspiration to the caustic how to's that will be presented in this tutorial. With that said, we shall now start the Real FX Studios GlassWorks (tm) Caustic Sampler Tutoial.

Note: You will have to excuse the poor quality renders (and their small size) i didn't want to take up too much bandwidth on a tutorial)

List of Required Software

Blender 2.34 - or earlier version equipped with yable exporter (beyond the scope of this tutorial)

www.blender3d.org

Yafray 0.0.7 - earlier versions may work but at the time of this writing it has not yet been tested by myself (if anyone has knowledge as to whether or not this does work please let me know).

www.yafray.org

PaintShop/Gimp - or other image editing software capable of increasing brightness, contrast, sharpness, noise, blur, or any other basic crop editing. This is not required but it does increase the image "realism" quality. Note: For those who don't want to spend money on fancy software a favorite alternative is Ultimate FX which can be found at www.ultimatepaint.com - this software is for windows and allows advanced
functionality over standard bitmap paint.

List of Required Skills

Intermediate Level - general use of blender buttons and layout, general 3d
navigation, general mesh editing capabilities, and material navigation.

Understanding Caustics

Edit:
Caustics Defined - caustics is the effect of metal and glass materials reflecting and refracting of light waves (photons) to a focused point. This effect is computer generated and produces the brights spots and streaks seen looking at glass with a spotlight on it. To demonstrate this effect put alittle water in a glass and holding it a few inches (10cm) away from a table and place a flashlight shining through it. Swirl the water around and you'll see caustics "dancing" on the table beneath.
/Edit

To fully understand caustics we are going to explain how caustics work
and show a few simple experiments with glass materials.

In Image 4 you will see the yafray panel and the yafray gi panel. The yafray panel has the following features that are most usefull in creating
caustics:

Auto AA
XML

These features allow for advanced testing and image creation. The first Auto AA is the anti aliasing toggle button that controls the smoothness of the edges and allows for greater picture quality when using Depth of Field (DOF). When on, the computer generates an anti aliasing value by using computer algorithms. When off, the user controls the anti aliasing. Under normal use, Auto AA is sufficient but when using DOF, it is best to manually set these settings (usually a combind setting of more than 120 will produce good enough results althoug higher is better).

The second feature is probably most usefull when it comes to actual render
time. When off, the rendering image is shown in its developement - usefull
for tuning and testing as it allows for faster veiwing times. As a rule i never enable this feature as with the latest version of blender 2.34 xml is not particulary needed (not to say not ever needed but generally the blender exporter can create images well enough without needing to modify the xml file).

The yafray global illumination (GI) panel is by far more usefull when creating beautiful and complex images. The settings are as follows:

Method (Full/Skydome)
Cache (ShadQu/Prec/Gradient/Refinement/Power)
Photons (Count/Radius/MixCount/TunePhotons)
Quality (None/Low/Medium/High/Higher/Best)
Depth
CDepth

Skydome Method limits the capabilites of the user settings but can produce
good enough shadows and lighting when enabled. As a rule i don't use it as
the Full Method is much better.

Full Method enables the use of user settings which, when set correctly, produce more realistic images with improved shadows and lighting. Cache is used to (and correct me if i am wrong as i don't have the manual in front of me) prestore the information used to render before actually rendering (which consequently makes the render pass shorter). In these setting you can control Shadow Quality (ShadQu), the shadow precision (Prec), the cache refinement, and the illumination power.

Also when Full method is enabled, the photon GI assistance is enabled. This feature allows for the computer to aid with creating realism with metal and glass materials. This is the basis for caustics. In this section you can set the number of photons that are to aid the other lamps (count), the radius that these are shot from (radius), and the blur values (mixcount), aswell as the capability of enabling the photon map to be displayed directly on the rendered image (tune photons) usefull when tuning photons.

The Depth and CDepth are for indirect and internally bouncing photon tracing

The Quality setting is for the quality of the illumination.

Also in Image 4 you will see the Photon Lamp panel and settings. This is where the caustics really come from - a photon lamp. This lamp works similar to the GI photon settings in that it shoots photons that are reflected and refracted by glass and metal materials. The number of photons shot is controlled by the Photons bar. The blur is set by Blur bar and the Search bar. And the depth that each photon will be "bounced" is set in the Depth bar. The Angle bar works just like it would with a spot lamp and just like a spot lamp you want the photon lamp to be pointing as concentrated as possible on the objects to be illuminated. The Use QMC button enables computer generated blur of the outer edge of the lamp circumfrence (again correct me if i am wrong as again i don't have the manual in front of me). All of these settings in conjunction create the beautiful caustics that you see in the finished image.

With that brief explanation of the yafray and photon panel functions we will
now jump into our first experiment.

Cubes for Simple Caustics


Cubic Caustics

Image 2 - http://img45.exs.cx/img45/732/image125.jpg
Image 3 - http://img45.exs.cx/img45/1495/Image361.jpg
Image 4 - http://img45.exs.cx/img45/3711/Image362.jpg

This first experiment is a simple experiment to test caustics and will be a beginners version where as the next experiment will be a more advanced
version. In this version we will make a cube on a plane add a glass material and create realistic three point lighting.

Start Blender and delete the default setup.

Go to the render buttons and set the renderer to Yafray and set the resolution to 800x600 at 100%.

Create the scene you see in Image 2. Set the photon lamp to the panel at the bottom of this image.

Now select the cube and go into edit mode and select all the vertices. Press
w -> subdivide and do that three times then press w -> smooth five times.
Now extrude and scale so that the sides are a little thicker. Subsurf twice and Set Smooth. Select all the vertices and press cntrl n to recalculate norms outside.

Then Add a new material and give it the settings in Image 3 and add a cloud texture mapped to cube, and nor (not col).

Add your favorite wood texture and material to the plane and then enable
traceshadow.

Check the camera view to make sure the scene looks like the camera view
in Image 2.

Then set the Yafray and Yafray GI Panel to that in Image 4.

!!Render!!

With any luck (good or bad) you will see Image 1 (or atleast something similar). If not backtrack till you find your error. Also you may want to use
your image editing software to increase sharpness and brightness or you
can create an overlay and use the blender sequencer to add a title to
the bottom of your image like you see in Image 1. Now that you have this mastered try experimenting with greater photon power and count. Colors and the like. Once you feel you have this undercontrol try moving on to the next experiment.

GlassWorks Caustics


GlassWorks Caustics

Image 5 - http://img45.exs.cx/img45/8366/Image363.jpg
Image 6 - http://img45.exs.cx/img45/6910/Image364.jpg
Image 7 - http://img45.exs.cx/img45/6795/Image365.jpg

In this experiment you will reuse the last experiments setup but will be adding a new object and using a different glass texture.

To accomplish this first go to the scene button at the top of your screen and add a new one (full copy). Delete the cube. Then save.

Now go to front view and create a vase using your favorite method (cylinder extract/spin) and make it similar to the profile in Image 5.

Place the vase on the plane level and move and scale so that the camera
sees the scene in Image 6.

Resize/Position your spot and photon lamp so that they point directly on the vase.

Now give the vase your glass material but change the cloud texture so that
it is now a voronio crackle cloud texture and use your favorite method to map it to the vase (i used orco->tube->nor/alpha/transluc since those values make for a fairly realistic marble crackle texture). Other variations could be used for more complex versions and what not so you may want to experiment some after completing this tutorial.

Because this new model is bigger than the last you will have to increase your photon count from 200000 to 400000 to achieve the same quality results. The GI Photon Count should be increased to 400000 or more aswell.

Although this has nothing really to do with caustics this will help your yafray images so we will dive into the gi panel cache settings. Set the
panel to Image 7. First thing to be changed was the ShadowQU from .9 to .945 this helps keep your shadows the best quality possible without passing the little warning when you hover your cursor over the bar. Next changed was the precision from 10 to 6 and the useless gradient was enabled. We refined the refinement bar to .050 and the power was left the same although if an area light was used the power would probably need to be upped to atleast 10. Also you will want to increase the Quality to Highest just for the fun of it.

Also you will want to set the AA value manually to 6 passes by 6 samples giving an AA of 36 (something inpossible to achieve with blender unless you couple 16OSA with 16 mblur samples!) As stated before should you use a complex scene involving DOF you will want to increase the passes to 20 or more and the samples to atleast 20.

After double checking all of your values...

!!Render!!

With a lot of good luck (cause that is all it is!) you will achieve GlassWorks(tm) caustics similar to Image 8. NOw that you have the basics of caustic creation and yafray and yafray gi panel functionality you may want to further experiment with photon lamp and gi photon count, photon lamp power, as well as alpha, nor and translucence mapping values, DOF, as well as multiple object and light scenes, on top of that you may want to test some metal only caustics (which take less time to render). If you should do metal materials remember that the lower the ref shader value
the better the "mirror" quality and 0 is a very common practice! Also remember that the alpha value is what controls the transparency values and that the raydepth in the material buttons is essential for realistic images.

Again you may want to use your image editing software to increase sharpness and brightness or you can create an overlay and use the blender sequencer to add a title to the bottom of your image like you see in Image 8.

Conclusion

I hope this has helped you and on behalf of the entire staff at Real FX Studios (and more specifically GlassWorks Images) i want to say thankyou
for you support.

If you have any questions you can PM me or reply to this post (please keep image submissions as thumbnails) or if you have any questions concerning the studio and it's commercial policies please contacts us at:

realfxstudios@hotmail.com

Thankyou,

Prince
Real FX Studios Administrator

[Prince]

I am going to be the first to respond to this aswell!



here is one of my many mistakes when writing this tutorial but it did make for good "black glass" and hopefully answers the guy (memory fails) who asked if anyone experimented with black glass!

I used the same material but with rgb values of 100/100/200 and alot of glow and some emit. The image isn't great but like i said it was a mistake and i decided to show it for fun.

Enjoy!

[effstops]

Cool! Thanks a lot, Prince.

*goes to try it out*

--Colin

Edit- w00t! Yay. It works.

[Caleb72]

Good stuff Prince.
I've been too lazy to work out all this caustics stuff and this puts it a bit more at my fingertips.

Thanks.

Caleb

[jts01]

Woo Hoo!!! Already copied & saved in a Word doc with all the images. Thanks a BILLION, Prince You, sir, are the man! :P

[digital_me]

When I try to render my caustics, yafray loads and everything, but gets stuck on 'loading parser.' Anybody have any idea why? (I got yafray v.0.0.7, and latest CVS build of blender.)

/d_m

[dhanielc]

Good work prince!!!
A lot of people will love this!

[Prince]

Originally Posted by digital_me When I try to render my caustics, yafray loads and everything, but gets stuck on 'loading parser.' Anybody have any idea why? (I got yafray v.0.0.7, and latest CVS build of blender.) /d_m

please say your os and system specs also can you render just the image without photon lamps? (send your lamps to layer 2 then render) also if this doesn't work try using just skydome gi lighting and see if it renders then. I say all this not neccessarily to help but for those who can this may help "trace" trace the problem back to some error you made (cause usually it is human error)

Possible reasons are memory maxing out, or system bus is boggled down to much. Also you should try using just blender 2.34 (not latest cvs build) and try again. But all in all more info is needed to solve your problem.

-------------------------------------------------------------------------------------

i just added a poll so vote!

[kryptolus]

The tutorial could use some extra commas %|
In some places the lack of commas makes a sentence hard to understand.
"When on the computer generates an anti aliasing value by using computer algorithms." You need to add a comma after "When on" otherwise it seems you're talking about "when you're on the computer". Same thing goes for the other times you use "When blah...".

You might also want to add a little description of what caustics is in the beginning of the tutorial before you go on to describe techniques.

Besides that, it seems like a great tutorial.

[digital_me]

Originally Posted by Prince Originally Posted by digital_me When I try to render my caustics, yafray loads and everything, but gets stuck on 'loading parser.' Anybody have any idea why? (I got yafray v.0.0.7, and latest CVS build of blender.) /d_m please say your os and system specs also can you render just the image without photon lamps? (send your lamps to layer 2 then render) also if this doesn't work try using just skydome gi lighting and see if it renders then. I say all this not neccessarily to help but for those who can this may help "trace" trace the problem back to some error you made (cause usually it is human error) Possible reasons are memory maxing out, or system bus is boggled down to much. Also you should try using just blender 2.34 (not latest cvs build) and try again. But all in all more info is needed to solve your problem. ------------------------------------------------------------------------------------- i just added a poll so vote!

I'm on window$ 2000, with a p4 1.8ghz and 512mb of ram, an ati radeon 8500 with 128mb of ram. I tried with blender 2.34, and it doesn't work. I read on the yafray site about them not working together (blender and yafray) because they're compiled with different versions of gcc. I can render with yafray just fine when using yablex, it's just rendering from blender that doesn't work.

/d_m

[Prince]

Originally Posted by kryptolus The tutorial could use some extra commas %| In some places the lack of commas makes a sentence hard to understand. "When on the computer generates an anti aliasing value by using computer algorithms." You need to add a comma after "When on" otherwise it seems you're talking about "when you're on the computer". Same thing goes for the other times you use "When blah...". You might also want to add a little description of what caustics is in the beginning of the tutorial before you go on to describe techniques. Besides that, it seems like a great tutorial.

thanks for the critic! i didn't notice that! sorry i'll fix those - i wrote it in a text document then copied it too the posting window and so i didn't have grammar correcting....

d_m: i'm sorry i can't help you there! :x i don't know how yablex exactly works (never used it but once) so i don't know if you can have caustics with that. The only things i can suggest is:

reformat and install winblows 2000 or window$ xp (if you can) then redownload 2.34 from blender3d.org then do the same for yafray 0.0.7 and see if it works

if that doesn't work it could be a graphics card problem or internal connection problem. do you have python installed? if not i'd install that (although it may not help it is always good to have it installed!) keep searching the forums and sites for information and if you get it fixed let me know!

[Auteuro]

Did you forget to put in material transparency settings (i.e., under the Mirror Transp tab)? After following your tutorial and getting no visible caustics, I found that I had to enable Ray Transparency and adjust the index of refraction (IoR) to make it work. Your tutorial is somewhat rough aroud the edges, but it's still very helpful.

[Blizzard]

I tried making your top tutorial with the cube, but it doesn't look right at all. I see a shadow, but i don't see much of anything of the highlighted or lightened part on the wood. Also, you can hardly see my cube, it just looks like two semi darker squares on the pictures. It doesn't have any of that black stuff around the cube (the reflcetion) or the highlight in the cube also. Can someone please help, or if u could link me to a source so i could see what i did wrong, thanks.

[encon]

A bit off topic but can you post your blender theme

[Wiggie]

http://www.frontiernet.net/~krich/themes/

[encon]

Glass material settings ?

[[a]drien]

yes, the Mirror / trans settings are not specified, it's very important, it's not working for me

[argunda]

I voted NO. This is a lame post and trying to make it a sticky is useless. First of all, The List of Required Materials was crap (waste of space and time). All you had to say was Latest Blender, Yafray, Image Editor (eg: Gimp).
As far as the turorial goes.. It could be summarized in One paragraph and the two images for the settings.

[Wasabe]

Aravinda what is your problem. Princes post was a great post. With the lastest stuff prince went out of his way to make this great tutorial for us, getting all the link and stuff, more work for him less for us. This is a great Detailed tutorial. i have wanted to know how to use caustics and this taught me. I would rather have this long lengthy version, then a tutorial a paragraph long. You call his tutorial a lame post u making fun of his post is Lame. Me making fun of your post is lame aswell but i had to say it.

[argunda]

Originally Posted by Wasabe Aravinda what is your problem. Princes post was a great post. With the lastest stuff prince went out of his way to make this great tutorial for us, getting all the link and stuff, more work for him less for us. This is a great Detailed tutorial. i have wanted to know how to use caustics and this taught me. I would rather have this long lengthy version, then a tutorial a paragraph long. You call his tutorial a lame post u making fun of his post is Lame. Me making fun of your post is lame aswell but i had to say it.

I wasn't making fun of his post, I was commenting it. If you don't like it, then stfu... seriously. I am sorry if you are not intelligent enough to understand a one paragraph tutorial but that is no excuse to post another post commeting my post. However, I think others would agree with me when I said All you had to say was Latest Blender, Yafray, Image Editor (eg: Gimp). It is concise and to the point. This tutorial is, in my god damn opinion, not good for a sticky. Besides the fact that Prince even posted a poll for it was futile. It would have been better to just PM an administrator or something.
Also notice that I wasn't saying that the content expressed in the tutorial was bad. Please read more carefully next time so you would not have to post that crap you did last time.