And now: Area lights!

General discussion about the development of the open source Blender

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Money_YaY!
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Joined: Wed Oct 23, 2002 2:47 pm

Post by Money_YaY! »

Here is an OSX Panther only version

http://aprilcolo.com/oh/plink/blender-2 ... rpc.tar.gz

eeshlo
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Joined: Wed Nov 06, 2002 10:02 pm

Post by eeshlo »

As for the exposure function, I originally got that from here:
http://freespace.virgin.net/hugo.elias/ ... posure.htm

but I was never really happy with the 'bleaching' effect it can have on colours, if stefano's modifications are better, I suppose we could use that in yafray too.

And about hdri support, that could be a possibility, since it would help yafray previews as well.

ada89
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Post by ada89 »

I never save the .blend but i manage to create another one with the same effect. I notice that i never turn the auto smooth function for the render and that actualy cause the weird stripe shadow.

Image
The stripe shadow on mesh is cause by not turning on the auto smooth (only the odd one was not auto smoothed )

http://sbup.jyscomputers.com/ada89/bugrend.blend

arangel
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Post by arangel »

Ztonzy posts binaries regularly on this Elysiun forum thread:
http://www.elysiun.com/forum/viewtopic.php?t=14924

Rangel

McGivrer
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Post by McGivrer »

arangel wrote:Ztonzy posts binaries regularly on this Elysiun forum thread:
http://www.elysiun.com/forum/viewtopic.php?t=14924

Rangel
and another link to get an exe for windows:
http://www.metalfx-zone.be/Data/30-12-2003.zip

A site from MetalFx a "francophone" Blender user.

Mel_Q
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Joined: Wed Oct 16, 2002 12:00 am

Thanks ton!

Post by Mel_Q »

Thanks for the area lamp- still expirementing with it.
Again, happy New Year and thanks fom New Orleans, LA USA.

http://myweb.cableone.net/rigel/fluerdeliscroix.jpg

macouno
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Post by macouno »

ada89 wrote: The stripe shadow on mesh is cause by not turning on the auto smooth (only the odd one was not auto smoothed )

http://sbup.jyscomputers.com/ada89/bugrend.blend
yeah something seems rather wrong in the auto smooth since version 2.30. Actually not just with auto smooth, but the entire smooth function. I keep getting odd results... the odd face suddenly being lighted when it should be in shadow or the other way around. And it's not a Normals issue.

Monkeyboi
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Post by Monkeyboi »

Slightly off-topic: There are problems when using Only Shadow and Ray Shadow together. Since you cannot turn down the opacity of raytraced shadows it is omportant that this works!

macouno
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Post by macouno »

I had another look at the black/shadow "face" appearing like in the stripe above. It's not the auto smooth but seems to have something to do with the angle of the lamp. I posted in the rendering forum, but well... it seems an issue with all raytracing lights.
Last edited by macouno on Wed Jan 07, 2004 2:26 pm, edited 1 time in total.

Analogy
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Post by Analogy »

Sorry if you thought of this already, guys, just trying to help. =D

There is a way to do area lights in a slightly less computationally-intensive way. The current method seems to use the brute-force method of using lots and lots of pointlights, which = tons (no pun intended) of render time.

The faster way is thus: When doing your shadow calculation, you trace a ray back from the point you're calculating for through each corner of each triangle in the scene (or at least those in the general direction of the area light), and test for intersection with the plane in which the area light resides. Effectively, you're "projecting" those triangles onto that plane from the perspective of the point you're doing the shadow test for. Now you just figure out how much of the actual area light is being covered up by those triangles, taking care not to count triangles covering the same area twice.

This method uses fewer rays than you use for the giant array of pointlights, and results in creamy smooth shadows.

Also, kinda OT, but it seems to me that the method used to draw reflections is a touch inaccurate... Reflections should *add* light to the object, not be an issue of alpha transparency. The final color should be the regular diffuse calculations, taking textures etc into account, then you simply use addition to put the reflection in.

Sorry I don't have code to back any of this up. I'd implement it myself but I was never really good at programming. Some day I'll learn a bit of basic programming and take a stab at it, I swear. =D

Oh, and please keep the selective raytracing options in when you implement full Yafray support... I don't want to take that speed hit every time I want to raytrace anything. Honestly, I don't know why people want full yafray support, the raster method works just as well, and it's a million times faster.

Dani
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Post by Dani »

I've been testing area lights...

Maybe it's just me, but i simply can't get satifying results in matter of quality, together with fast render times. Even in low resolution, you have to set samples at 16 to have the softest shadows possible, and that takes a LOT of time. A lot longer than exporting to yafray...

Hum, so maybe there's a way to optimise these rendering times...
And I also liked the soft shadows for all lamps? I don't really think that having area lights in is a reason for putting soft shadows out...

My 2 cents...

Dani

Monkeyboi
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Post by Monkeyboi »

Analogy: You are right, area lights can be alot faster! Try them in Cinema 4D - COMPLETELY smooth results and 1000 times speed. Your method seems to be a good one, but I don't know if there are more ways to do them. There must be a few documents lying around on the net about this.

Its all about speed speed speed, remember who cares if you can create 100% photorealistic renders if it takes five days to render? Not saying Blender takes five days, but it isn't exactly fast to be honest

madprof
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Post by madprof »

Its all about speed speed speed, remember who cares if you can create 100% photorealistic renders if it takes five days to render? Not saying Blender takes five days, but it isn't exactly fast to be honest
Don't be silly. What "its all about" is creating art. Producing the image/movie/model that you have inside you. If it takes 5 days to render, yes, thats a long time to wait, but if thats the only way to get the correct result, then so be it.

For animated movies and effects, rendering of a section of movie can take weeks. If it was only about speed, then they would just drop the lights, make everything low-poly, and who cares about it being unrealistic? Its not like that though. In movie-quality work, you need it to be photo-real so it blends in correctly.

This is why blender+yafray is so great. Blenders renderer is fast. But it cannot compete with Yafray for true photo-realism, and other advanced rendering. Every tool in blender, the renderer, or yafray makes the tools better, allowing artists to make their art closer to what is inside them.

Of course, I'm not against speed, :-) the quicker I can get renders, the better, obviously, but if it means sacrificing quality, then No Way.

Anyway.

Dan

Monkeyboi
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Post by Monkeyboi »

Okay okay... Ofcourse I love Blender and I think it is great that it is possible to achive these great results. And true, it's better to have slow area lights than no area lights, and better to have slow raytracing than no raytracing.

Anyway, I wasn't talking about sacrificing quality, I was just pointing out that Blenders area lights are extremely slow compared to other renderers (with worse results).

I'm not bashing Blender, just saying this paricular thing could be better. It is a common thought that raytracing has to be extremely slow, but that is not exactly true. I have used XSI, and Mental Ray is probably faster than Blenders scanline rendering!

ton
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Post by ton »

We're now working towards an official release, and the area-light soft shadow definitely won't be presented as the superior new technology that will end all other shadow methods! I'm not satisfied with the speed as well, another reason not to add it to all lamp types yet.

I've added features to the renderer mainly to show it is possible to do, and because it was really needed to move this old render code from the early nineties to a bit to contemporary standards. :)
Hopefully the release will inspire others to check on the code and rendering, and help with ideas how to improve it.

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