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Re: Light & textures - rendering examples of this and that.
colour of the sunlight varies, not only by the time of day, but also by the time of year – and so do the shadows
Took a second look at your sundial illustration. Not sure how you generated the image, but if it was SH3D/Sunflow (with a non-daylight-saving time setting close to the middle of a time zone), it looks like it might actually be equation of time(?). In which case I was wrong in my last post and our Azure home banter. Interesting. ok
Denmark
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Re: Light & textures - rendering examples of this and that.
it looks like it might actually be equation of time(?)
Probably. The images were ( of course ) created with SH3D/Sunflow. Time zone is GMT + 00:00 and physical placement is Greenwich Park.
So the equation of time is responsible for the wobbly shadows...
In other 3D-programs ( like f.i. Vue eXtream – where I got my first real 3D experience) the sun is just a directional light source used to create atmospheres, so you can grab it and move it about as much as you like. Even if it's a lot more complicated in SH3D, I try to use the sunlight the same way, so I often shift the date and time to change the colour and height of the sunlight. That's why I created the sundial – to observe how both the light and the shadow directions changed with time.
Here is my sundial Project-file, so you can inspect my setup.
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Re: Light & textures - rendering examples of this and that.
Thanks. After some experiments it certainly looks as if the rendering considers equation of time.
..more complicated in SH3D, I try to use the sunlight the same way, so I often shift the date and time to change the colour and height of the sunlight...
And you make it work nicely for your renderings. But for me it would only be confusing if I could shift the sun at random, so I am happy it is 'complicated' to 'cheat'.
Anyone coming across this thread and reading about the sky texture alignment, should also know that SH3D 6 (beta 7) introduces X offset for the sky texture so it can be rotated.
Denmark
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Re: Light & textures - rendering examples of this and that.
@okh
Anyone coming across this thread and reading about the sky texture alignment, should also know that SH3D 6 (beta 7) introduces X offset for the sky texture so it can be rotated.
Your contributions here are boosting the value of this thread. Thank you!
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Re: Light & textures - rendering examples of this and that.
Oh well, I am just meddeling. Really appreciate your detailed guide. Meanwhile I am updating my .svg template. Not posted yet. Template works quite well for inserting own images, but when I try to use 3d matrix to recreate your backdrop distortion I run into all sorts of problems. In part it is not supported by Inkscape (and not all browsers), but more annoyingly, even if the image transforms well, it somehow gets so blurred that it is totally useless. But I am on the case. One day maybe a proper man-template will be available. Meanwhile I suppose we shall have to make do with the (better) upside down world. ok
Denmark
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Re: Light & textures - rendering examples of this and that.
even if the image transforms well, it somehow gets so blurred that it is totally useless.
It's your fear of high resolution that is blurring your vision!
My sky images are 15000px x 3750 px. I normally go at least twice that size when editing, and then rescale to 15000 x 3750 px ( or sometimes as low as 6000 x 1500 px if there are no gradients present).
The jpg-compression algorithm can be tricked by adding a layover of noise, so that even at the lowest (10%) jpg-quality a 15000 x 3750 image will render an acceptable sky at FoV 30. A 15000 x 3750 low-res jpg @ 10% can weigh as little as 200kb, and still render ok. For sky images, resolution (size) and quality goes hand in hand.
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Re: Light & textures - rendering examples of this and that.
It's your fear of high resolution that is blurring your vision!
That could very well be, actually. As you know I work with scaled down images for templates and tests even if I am not quite as cheap with my more private projects.
Still, there is something strange. I can transform the image quite well in the Gimp. But when I try to use .svg so a linked image can distort automatically, I get problems. Cannot remember how intimate you are with .svg, but here is the latest attempt using .svg + css3 to test 'automatic' 3d distort in the template (viewBox="0 0 360 94" ). In Firefox, the rectangle and image distorts, but is too blurred.
<!-- In theory this could distort (transform) an image to improve rendering, but it is not supported by several browsers/Inkscape, and when it is supported (Firefox), the image blurs --> <g transform="translate(30 60)" opacity="1"> <g style="transform-origin: 32px center 0px; transform: matrix3d(1,0,0.00,.00,0.00,1,0.00,0.01,0,0,1,0,0,0,0,1);" > <rect width="72" height="36" fill="none" stroke="red" stroke-width="1"/> <image width="72" height="36" xlink:href="mountainx.png" preserveAspectRatio="none"/> </g> </g>
When I can spend a couple of hours to concentrate, I will try some more before I post the template. For the record, this is not an attempt at picture perfect, just a quick approach to create a backdrop that can work with a SH3D scene render. ok
Denmark
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Re: Light & textures - rendering examples of this and that.
Cannot remember how intimate you are with .svg,
Not at all intimate I'm afraid But I'm quite intimate with Photoshop, and I know for a fact that scaled down images will produce crappy outputs.
Okay... We have talked about this before.
A 1024 px image at maximum jpg-quality will not produce an acceptable sky image, whereas the same image at 6000 px, compressed so much that it's weighing the same (both weighing 150 kb), will produce a far better ( almost a tolerable) sky rendering. Examples: Sky image 1024 px - Filesize = 150 kb:
Same image 5700 px - Filesize = 155 kb:
Size matters (resolution – not filesize), not only for the sky, but for ALL textures, and the higher the resolution – the more compression can be applied – ergo: The filesize is less important than the resolution.
I prefer sky images @ 15000 x 3700 px, and they normally weigh between 800 kb and 2.1 Mb.
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Re: Light & textures - rendering examples of this and that.
..quite intimate with Photoshop...
Picking a tool is a matter of choice. My preference is Gimp for the raster images, which I link into an .svg file for post editing with a text editor or Inkscape. Doubtless, this could be done with the Gimp alone, or Photoshop, with just as good results. The only reason for the .svg detour, is that items easily can be placed, moved, scaled accurately on the canvas by using numeric co-ordinates. And then each item, a hill, a cloud, can be adjusted individually with the Gimp (or whatever) to acceptable resolution, hue etc. etc. But that is just a personal preference.
We have talked about this before.
Yes we have. And, of course, I agree with what you say. Just did a test using the .svg template (which I will post) exporting to .png. at: 7200×1880, 3600×940 and 1800×470. With 6.0 beta and limited access to memory, 7200×1880 maxed out. 1800×470 rendered quickly. The latter is acceptable for planning purposes, but even I would consider using higher resolutions for a nice render. Which is to say, I agree with what you say even if I probably have a lower threshold for crappy.
Denmark
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Re: Light & textures - rendering examples of this and that.
With 6.0 beta and limited access to memory, 7200×1880 maxed out
Yes, that's the problem with the web-start-version.
The only reason for the .svg detour, is that items easily can be placed, moved, scaled accurately on the canvas by using numeric co-ordinates. And then each item, a hill, a cloud, can be adjusted individually with the Gimp (or whatever) to acceptable resolution, hue etc. etc.
Sounds a lot like what I do in Photoshop. I don't think I have fully understood how the .svg numeric coordinates work differently than a Photoshop ( or Gimp) template.
) created with SH3D/Sunflow.
