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Author Topic: I have an architectural project (Several Question)  (Read 11664 times)
February 28, 2010, 11:14:57 pm
Hello guys.
Snapshots that you see are for my recent architectural project that iam working on. Those are software render and i dont build them. Just a preview.

So my question.

1. HDR and AA.
As far as i know its impossible for now. right?

2. Bake lots of complex specular.
ATI have a paper for that http://www2.ati.com/developer/gdc/D3DTutorial10_Half-Life2_Shading.pdf
But i dont think it would be accurate for my project. Any better solution?

3. Reflection and refraction for lots of glass.
As you can see there is lots of glass. Is there any tip for such a situation?

4. Dose clear Thick galss recived any lighting at all?

5. HDR and ATI.
For ATI vga its better to use 16 or 32 bit HDR?

6. Motion blur.
Dose anyone have a motion blur based on vector? (Like crysis). I want to buy it.

7. Best way to combine lightmap with tile texture.
As you know most common way is to multiply them. But when there is a over bight area in lightmap (For example near light source) multiply method dont over bright those area. One way is to use hdr lightmap with hdr post process. But is there any other way?

8. 16 vs 32 bit HDR.
What is big different? performance? Quality? Or both? Or its depend on vga model?

Thanks a lot.


* 01.jpg (142.59 KB, 1800x1350 - viewed 321 times.)

* 02.jpg (116.73 KB, 1600x1200 - viewed 321 times.)

* 03.jpg (201.29 KB, 2000x1500 - viewed 333 times.)

ali-rahimi.net
March 02, 2010, 02:46:05 pm
Nobody interested?  Undecided

ali-rahimi.net
March 02, 2010, 03:07:32 pm
These are all very difficult questions, but of course we're all interested in the answers Wink

1. It's possible, but we need a workaround from Act-3d to do it in Quest. For now, you can use Viktor's post processing AA, but it's not as good as hardware AA.
March 02, 2010, 03:45:44 pm
Thanks Peter.
I tryed Viktor's post processing AA. Its far from hardware AA. What about other questions?

ali-rahimi.net
March 02, 2010, 07:08:32 pm
Personally I would add some modelling details to the scene to make it more realistic:

For example, where are the light sources?
March 02, 2010, 09:09:26 pm
Its just a test that some guy made. Its not mine. Final work is much much more better. Those snapshots are sucks.  Grin

ali-rahimi.net
March 02, 2010, 10:58:08 pm
1. In DX9 there are 2 ways to do AA: The first method is to do render a pre tone map HDR image. This method is not as good as post tonemap AA since the tonemap changes the ratios of pixel values. In practice you will see that this results in no antialiassing in areas of high contrast. The second method is to do tone mapping in the shaders and write tonemapped images to a 8 bit buffer which has AA. This method is difficult because the HDR image is needed to set the exposure value for the tone map. Since you do not render a HDR image you need to use a different method to get the exposure value. You could, for example use MRT and write HDR Luminosity to a 32bit HDR single channel texture. DX9 allows writing to a ARGB8bit and R32 bit texture at the same time. Possibly you could conver the 8 bit HDR texture to YUV and use the 8 bit UV channels with the 32 bit Y channel to get a good approximation for HDR postprocessing effects such as bloom, flare and lens reflections. You can also do the post processing in luminance only. Probably you can get away with having white bloom only.

2. Specular lookup means you create a bunch of cube maps to simulate specular of many point lights. Imagine 10 cube maps positioned around the camera. You will have to select these cube maps dynamically and render an approximation for the lights from that position. The closer a cube map is to the surface you are shading the better this approximation. If you had a cube map for every single pixel of the surface it would be perfect. The trick is to generate the right cube maps. On the other hand you can also go for a simpler approach. Make it so each object is not too large. Next, select a limited number of lights (limited by range for example) for each shader.

3. Same as with question 2. Reflection is the same as specular lighting. If you do a HDR cube map of a posion and have the lights as very bright blobs in the cube map you have specular lighting. The problem ofcourse is that a cube map is not good enough for flat reflections. People expect a perfect reflection on a flat surface. The only way to do that is by rendering the scene inverted on the reflection plane and use the resulting image in your shader. We do it all the time for water but for a building you have many surfaces so it might be difficult. Usually a perfect reflection is used on a mirror or the floor and all other surfaces use an approximation by means of a cube map.

4. No and yes. Perfectly clear glass does not receive any light. It bends light and reflects light. Dirty windows do reflect light and they behave exacly similar to normal diffuse windows. You can easily simulate dirt on a window by rendering two seperate materials and using a lerp so show or hide one or the other.

5. In general 16 bit is better as long as you do not see banding. 16bit is smaller so it saves half the bandwidth.

6. I doubt if it is available. Pretty difficult to set up. You need to render using MRT. Your shader needs to write screen space speed to a texture, with this texture you blur the scene. For normal objects you need to pass the worldviewprojection matrix of the current and last frame toyour shader and store the difference of the resulting screen space positions.

7. Easy: make sure your light map extends beyond the 0-1 range. One method is to darken all your light intensities and save normal light maps. In your shader you multiply the light map so the lights have their normal brightness. The best way to so it ofcourse is to use HDR textures.

8. Visually there's no diference in most cases. Performance wise 16 bit is faster because of reduced bandwidth requirements. Also note that some cards cannot interpolate 32 textures so things look blocky.
March 02, 2010, 11:42:47 pm
Thank you so much Remko for your time. Iam working on this project full time. Its a hell a lots of work. By the way turtle 5.1 is getteng even much more better. Now we can render and bake OCC directly with FG.

ali-rahimi.net
March 07, 2010, 02:21:24 pm
Snapshot from basement in progress.


* a1.jpg (163.03 KB, 1024x768 - viewed 324 times.)

ali-rahimi.net
March 07, 2010, 02:37:29 pm
That looks very nice and clean, Ali. Great job! Smiley

I guess you're doing the baking with Turtle, but is the unwrapping done with Maya's standard tools or are you using a plugin to get such a nice result?
March 07, 2010, 02:49:07 pm
Thanks Peter. This shot is software render (Turtle). I dont bake it yet. For UV mapping i always use maya standard tools. The trick is how to use unfold tool.

ali-rahimi.net
March 07, 2010, 09:19:11 pm
Are the reflections of the white lamps "real"?
March 07, 2010, 09:23:30 pm
Yes. But its software render with Turtle. Turtle is very fast in both rendering and baking.

ali-rahimi.net
March 09, 2010, 12:20:49 pm
Ok. I made some test with 32 bit lightmap and gamma correct for tile texture on/off


* tile texture gamma correct .jpg (91.51 KB, 1024x768 - viewed 295 times.)

* tile texture non gamma correct .jpg (81.62 KB, 1024x768 - viewed 283 times.)

ali-rahimi.net
March 09, 2010, 03:15:47 pm
It looks more similar to the software rendered picture than the non-gamma corrected version.
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