Finis' Experiments and Scribbles

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Finis
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Finis' Experiments and Scribbles

Post by Finis »

Here is a test of instancing in Daz-Iray. There are 600 instances of the sci fi tube and dude. Approximately 24 million instance polygons. After 18 minutes of rendering it was 3% done. Only 250mb of video card memory used so many more instances could be used.

Things learned: Use a geometry shell for the character. Much faster than full character. Use solid bounding box for screen display when possible. All the instances really slows UI response. Make things invisible when not using them. Light emitting surfaces can be used with instances. The "sun and sky only" and "dome only" lighting options don't effect light emitting surface light. It is still there. Use base resolution no subD character unless high poly subD is needed. To copy groups of instances use the duplicate group hierarchies tool on edit menu.
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PeopleTubesInstancesEXP.jpg
PeopleTubesInstancesEXP_1.jpg
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Re: Finis' Experiments and Scribbles

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Trying a realistic render. I did not make any of these items. The 1968 Firebird is from http://www.tf3dm.com" onclick="window.open(this.href);return false;. The bushes are Bryce trees. The ground and wall are planes. The materials come with Daz-Iray or are textures I already had. Rendered with Iray in Daz. Render time 15 minutes. Some post processing for contrast and brightness in Paint Shop.

I tried an HDRI image as the visible environment but it was always too fuzzy. Seventeen megabytes of image. How do I get clear HDRI environments so I put objects in them without building an environment from models?
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Firebird1968.jpg
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Re: Finis' Experiments and Scribbles

Post by RAYMAN »

Finis wrote:Trying a realistic render. I did not make any of these items. The 1968 Firebird is from http://www.tf3dm.com" onclick="window.open(this.href);return false;. The bushes are Bryce trees. The ground and wall are planes. The materials come with Daz-Iray or are textures I already had. Rendered with Iray in Daz. Render time 15 minutes. Some post processing for contrast and brightness in Paint Shop.

I tried an HDRI image as the visible environment but it was always too fuzzy. Seventeen megabytes of image. How do I get clear HDRI environments so I put objects in them without building an environment from models?
Very easy Finis you need HDRI's with an awsome amount of size!
Its a very nice render you made..you are getting there!
When I make the enviroments I use Sketchup..even the free version works well
and make the Hdr's inside my landscape 3d app..the hdr can have lower pixel count since
I can use the portion of the stage...its more realistic!;)
If you need to use HDR only the best bet is to split your hdr...
some people use a very long lens and take a picture of a sphere...like
a christmas ornament with an average resolution and then the portion on which
the 3d object should stand with a very high res....you then
res the low pix part up to match the high res part in ie Photoshop
or Gimp and copy them together...they dont have to match 100%
Since you only see the low res in the reflectiob of your 3 d model...
Note though that the size of your HDR inside the app will be incredibly large..
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Re: Finis' Experiments and Scribbles

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I'll try another image of this car using the default blurry Iray HDRI for light and the modeled surroundings. This one used sun and sky lighting. I'll also try one with an ordinary format spherical image on a sphere as a light emitting texture.

This HDRI thing is starting to be silly. Thanks for the advice Rayman. However, it seems the work-arounds to make HDRI backgrounds useful is just going back to IBL or a sphere with a light emitting texture maybe plus a backdrop plane or other shape with an image. Since HDRI apparently doesn't work well without many troublesome work-arounds why use it? Here are my thoughts presented so I can be corrected and educated about HDRI.

-- I like the idea of IBL. The lighting puts the objects in the environment. The environment being a photo for realistic renders avoids detailed realistic modeling of things that aren't the main items. For instance, it would take much work to get my plants, wall, and ground to match the realism of the car. I'm not seeing an advantage to huge HDRI files nor their characteristics.

Claim: Lighting from an HDRI image is better.
-- The effect of brightness and color from different directions is present in regular IBL or light emitting sphere.
-- HDR images can represent very bright pixels and subtle variations of color. Thus "high dynamic range". Since normal humans can see about one million colors unless you are a tetrachromat (link) you can't see these colors.
-- The ultra resolution of the images is not needed for lighting so the huge file size is wasted. HDRI enthusiast's own methods show that it is not needed since they sometimes produce or use "convolved" images which are intentionally blurry for lighting.
-- We don't have screens with a brightness that would blind you by looking at an HDR image of the sun so the extra brightness won't be seen. It could be that the extra brightness in HDRI's produces some subtle lighting difference in an ordinary dynamic range render but I doubt there is any significant improvement to a viewer's perception of the render.

Claim: HDRI is good for background environments.
-- Since the enormous files just produce blurry backgrounds while smaller normal format image files look great on a background sphere this is obviously not true. Why use a huge file when a smaller one works great?
-- I can see possible problems with non-super-resolution spherical images looking good at a distance but looking bad closer. I think that could happen for example under the car in this image. So work-arounds would be needed for non-HDRI too.

Claim: HDRI is good for reflections.
-- Blurry images are not good for reflections and only HDRI's of unimaginable size are clear.
-- Smaller normal format images look great on background spheres and thus in reflections. Why use a huge file when a smaller one works great?

High quality huge HDRI's are expensive or rare as free or cheap. Spherical (Mercator projection, typical sphere UV map) normal format images are more available. Rarity and expense means that illustrators would use fewer of them leading to monotony. "Oh not a car in THAT parking garage again."
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Re: Finis' Experiments and Scribbles

Post by RAYMAN »

There isnt a big difference between ibl and hdr!!
The only difference is that you need different exposures
of the same ibl to make the hdr! Thats it.. nothing else!
Hdr is basically ibl!;)
In many hugh productions including ILM productions..Star wars
etc they arent using Hdr as a backdrop.. but are jusz making plain
high res pictures..this art ist called matte painting!
I never ever payed for hdr's! Its one of the best treats of Vue that even
the most basic version can render Hdr' s and export either as exr
or other format.. and for many forums I ve hosted these as giveaways..
Hdr' s have a higher dynamic range and give the tender engines
more legroom to calculate the highlights and shadows..thats all there
is to it ! Even 2000 x 1000 is enough for lighting only..if you dont use
it in your scene..!
If you want to make hdr with photography you need to splice the speric
ibls together and make different exposured versions of these
and run them through hdr merge software...Photoshop has it on board
natively!
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Re: Finis' Experiments and Scribbles

Post by RAYMAN »

update ! I Pm´d you about how you can do it for free..
But here is the step by step......
1. Downloaded the model and converted to file Format that it can understand..
2. dispers it... in this case with eco brush
3. render to Screen as Panorama..... Chose max size possible..
4. save as jpeg for Ibl OR......
5. Save as HDR or EXR .. for HDR like......
6. Import into Truespace as IBL and render..... OR Import into any other as HDR...... itrs basically not very different
Note that you can also render as sphericals if that is what your app loads.....!!!
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render ball ibl.jpg
wen ibl.jpg
screen.jpg
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Re: Finis' Experiments and Scribbles

Post by Finis »

Thanks Rayman. That's a cool feature of Vue. Great for landscapes and using models in them for environment spheres. Doesn't help with avoiding modeling things other than the hero objects but that's what do-it-yourself, buy it, find it, or "you gotta model it this time" are for. If I had Vue I would put the stuff in there and render with it.

Yeah the basic idea of light from an env. sphere is the same IBL or HDR. Still need lots of pixels but HDR files are bloated with extra bits for HDR when normal DR would be fine. I think the results are not perceptibly better.

New tests attached. One uses the default blurry HDR image for Iray and one uses a 273mb hdr sample from Dosch Design. It is permitted only for testing. The default one looks good except blurry reflections. I'm happy with the Dosch HDR one except for the file size and my gripes about the cost/rarity of cheap or free big, quality, HDR photos. Amazingly, the big HDR one rendered in about 3 minutes!

I also tried a 4096 wide jpeg in spherical projection as a light emitting texture. More pixels are needed for the background to look good but the lighting on the car was ok. The main problem was that making the light emitter bright enough made the background look bad.

So HDR alone is ok if I can get or make a big enough, high res enough, file. Otherwise use a back drop. Yes matte painting.

Edit: I've read that Daz Iray currently has issues with the clarity of the HDRI images. They are said to behave unpredictably and may be clear or not.
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Big HDRI
Big HDRI
Default HDRI
Default HDRI
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Re: Finis' Experiments and Scribbles

Post by Finis »

Experiment with Daz-Iray for a tea cup with tea. I'm interested in caustics and speed of rendering. The tests rendered for 4 minutes each. The path tracing (bdpt) produced caustics the fastest reaching 84% finished and 229 iterations. Metropolis light transport (mlt) with caustics was very slow reaching less than 1% finished. However, the images look similar to the bdpt ones so maybe number of iterations is the best measure. Mlt will produce some caustics itself and that is starting to show in the image.
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bdpt.jpg
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Re: Finis' Experiments and Scribbles

Post by Finis »

Accidental Art. Fooling around and this happened. Some fine tuning after I saw it looked good. Any suggestions for a title?
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Re: Finis' Experiments and Scribbles

Post by Draise »

The Virus.
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