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Author Topic: Which forum for novice queries?  (Read 3189 times)
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terrypin
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« on: August 19, 2007, 03:31:56 PM »

Just registered here with the aim of asking some very basic questions. But at first sight I don't see any appropriate forum.

Maybe if I give an example of the sort of question I have in mind,someone could point me to an appropriate resource, either here or at another site please.

EXAMPLE:
I installed a program called Apophysis recently but am having trouble getting started. One very basic confusion I have concerns 'rendering'. From my limited hobbyist experience with DVD editing/authoring, I expected to get a video as the final output from the program. Which I could then play externally. Effectively displaying a larger version of what I see in the Apophysis Preview window, either on my PC or (as part of a DVD) on my widescreen TV. Something like the fascinating video demonstration I've just seen of another program called 'Electric Sheep'.

But all I get from 'rendering' is a single JPEG, a mere 1 MB. Yet the dialog appears to be telling me the render will use 96 MB. And it took 4 mins  to produce it! So what was it doing for 4 mins?!

Neither the Apophysis Help file nor the couple of introductory tutorials I've found help me with this, so I'm guessing it will prove embarrassingly obvious!

More generally, is there a really basic introduction for a beginner like me to which someone can point me please?

--
Terry, West Sussex, UK


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lycium
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« Reply #1 on: August 19, 2007, 04:06:47 PM »

apophysis focuses on producing single images, and rightly so: it's really damn slow. the electric sheep thingy (a screensaver i think) produces animations by pooling together the computational (and network) resources of thousands of computers, which render frames and send them back to scott draves so he can sell it to companies in $10k installations. about the memory usage, to generate such images requires a high dynamic range histogram, so each pixel uses 16bytes or more. considering that each of those pixels / histogram bins have to be hit tens of thousands of times to produce a smooth image, and that apophysis is written in an ancient language called delphi, it's not difficult to see where the rendering time goes either wink

word on the street is that *ahem* some people are working on flame renderers that are between 5 and 100 times faster than apophysis/flam3, but they're not ready for public consumption yet...

ah yes, and welcome to the forum smiley
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lycium
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« Reply #2 on: August 19, 2007, 04:10:53 PM »

about tutorials: i have no idea how to use it myself, but perhaps The Mighty Google knows...

http://www.google.co.nz/search?q=apophysis+tutorial&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

begets

http://apophysis.deviantart.com/journal/2038750/ (see under tutorials)
http://sya.deviantart.com/art/Apophysis-Tutorial-10781352
http://www.thefractalfarm.net/203a/Main/203aindex.htm

etc...
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terrypin
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« Reply #3 on: August 19, 2007, 05:11:13 PM »

Thanks for both posts, lycium, appreciate the fast response.

I'm sorry to be so dense, but the penny still hasn't really dropped for me here! Putting my query at its most basic: why do I need to 'render' at all? Why can't I just capture with my keyboard's Prt Scrn key what's displayed in the Preview window?

Re tutorials, I've been ploughing through google hits for quite a while, but I have yet to find one for the absolute novice, taking me through a few simple worked examples. I'm sure it will all become blindingly obvious once I've done a bit of learning-by-doing  wink

--
Terry, West Sussex, UK
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lycium
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« Reply #4 on: August 19, 2007, 06:00:18 PM »

Thanks for both posts, lycium, appreciate the fast response.

that's ok, it's only 4am here wink

why do I need to 'render' at all?

because the preview looks poo tongue stuck out the preview renders as quickly as possible so you can get an idea of how it'll look like once properly rendered. for example, if you were to wait for something like this everytime you changed your settings, that would suck: http://www.fractographer.com/test3/temptress%20fullsize.jpg (beware, 37mb jpeg)

Re tutorials, I've been ploughing through google hits for quite a while, but I have yet to find one for the absolute novice, taking me through a few simple worked examples. I'm sure it will all become blindingly obvious once I've done a bit of learning-by-doing  wink

if you find a good one, please link back here as i'm also trying to learn it -- i'm writing yet another flame renderer, this time finally with a user interface, so i probably need to know how to use it before i start really working on the interface.
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terrypin
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« Reply #5 on: August 20, 2007, 08:32:48 AM »

because the preview looks poo tongue stuck out the preview renders as quickly as possible so you can get an idea of how it'll look like once properly rendered. for example, if you were to wait for something like this everytime you changed your settings, that would suck: http://www.fractographer.com/test3/temptress%20fullsize.jpg (beware, 37mb jpeg)

Neat. I downloaded it and, as expected, I can view its high quality on my 1024 x 768 screen. Initially, at full size, that looks about the same as say a 1 MB version, but that latter would indeed look 'orrible as soon as I start zooming in on a section. I realise that of course. But that doesn't answer my question about why I get just a small size file after rendering in Apophysis.

For example, I just opened the program, selected the third title from the top, Apophysis-070820-3, waited a couple of seconds for it to display, decided I liked the look of it, and clicked 'Render to disk'. That's running as I finish typing this, and tells me it needs 68 MB, and the filename will be Apophysis-070820-3.png. OK, after several minutes, it's now finished, so I can examine the file. It's 1.3 MB, and when opened in IrfanView looks very similar to the image displayed in the Apophysis main window. Which I could capture in an instant with Prt Scrn, crop, and get a file of identical resolution. What am I missing? Is there perhaps also a 68 MB file somewhere I haven't discovered?

As a side issue, what exactly do users of Apo and similar fractal generating programs typically do with their finished results please? Like the one you have demonstrated above? Is it just a matter of viewing, with repeated zooming to see the richness of the underlying structure? And maybe taking screen captures of the 'best' of these? Or am I missing some other fundamental aspect?

Quote
if you find a good one, please link back here as i'm also trying to learn it -- i'm writing yet another flame renderer, this time finally with a user interface, so i probably need to know how to use it before i start really working on the interface.

Sure will, but I'm losing hope of finding one...

--
Terry, West Sussex, UK
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Nahee_Enterprises
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« Reply #6 on: August 20, 2007, 08:41:38 AM »

Just registered here with the aim of asking some very basic questions. But at first sight I don't see any appropriate forum.

Basic questions concerning the use of a particular fractal rendering application would fall under the "Fractal Software" category, either under the "Help & Support" board or the "General Discussion" board.
« Last Edit: August 20, 2007, 08:43:29 AM by Nahee_Enterprises » Logged

lycium
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« Reply #7 on: August 20, 2007, 08:46:16 AM »

Neat. I downloaded it and, as expected, I can view its high quality on my 1024 x 768 screen.

i was pleased to read that you use a high quality program like irfanview for viewing images; most applications (e.g. all web browsers!) do a horrible job and introduce jaggy artifacts when resizing!

Initially, at full size, that looks about the same as say a 1 MB version, but that latter would indeed look 'orrible as soon as I start zooming in on a section. I realise that of course. But that doesn't answer my question about why I get just a small size file after rendering in Apophysis.

it was an extreme example just to illustrate the purpose of preview vs final renders; also that wasn't made with apophysis but my own program, hence the disgustingly high resolution wink

For example, I just opened the program, selected the third title from the top, Apophysis-070820-3, waited a couple of seconds for it to display, decided I liked the look of it, and clicked 'Render to disk'. That's running as I finish typing this, and tells me it needs 68 MB, and the filename will be Apophysis-070820-3.png. OK, after several minutes, it's now finished, so I can examine the file. It's 1.3 MB, and when opened in IrfanView looks very similar to the image displayed in the Apophysis main window. Which I could capture in an instant with Prt Scrn, crop, and get a file of identical resolution. What am I missing? Is there perhaps also a 68 MB file somewhere I haven't discovered?

the 68mb is being used by apophysis internally, it's not saved as far as i know and it's also not directly viewable. that's the 16-bytes-per-pixel storage i mentioned, it holds the raw histogram data apopysis uses to produce the final image. if you find the disk-rendered image is the same as the one in the preview, turn up the quality settings smiley the idea is to get an image which is truly something to marvel at... on the subject of which, if you're not marvelling at many of the fractal images produced with apo, you might well be missing the point wink spend some time going though these galleries:

http://zueuk.deviantart.com/
http://psion005.deviantart.com/
http://halcyon83.deviantart.com/
http://mobilelectro.deviantart.com/
http://joelfaber.deviantart.com/
http://michaelfaber.deviantart.com/

that list is by no means exhaustive, but i have it handy and it's fairly illustrative. why do people make fractal artwork? to display skill, for self fulfilment, to pass time, ... smiley if you don't see any reason to do it, don't force yourself tongue stuck out

Sure will, but I'm losing hope of finding one...

i'll be investigating these soon: http://browse.deviantart.com/resources/tutorials/digiart/fractalart/?order=5
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doncasteel8587
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« Reply #8 on: August 20, 2007, 03:18:52 PM »

.....when opened in IrfanView looks very similar to the image displayed in the Apophysis main window. Which I could capture in an instant with Prt Scrn, crop, and get a file of identical resolution. What am I missing? Is there perhaps also a 68 MB file somewhere I haven't discovered?

Terry,

Some flames do not need super high quality, especially if they are very hard edged. A flame with hard, descrete shapes seperated by hard empty space doesn't gain much from additional sampling. (although more is still better)

However a flame with delicate wispy transparent regions, like smoke curls, or overlaping layers of very sheer cloth, are extreemly hard to get nice quality even with super high sampling.

One way I gage how much difference high sampling will make is to check the difference from the small preview in the transform window to the main preview image. If you can see most of your flame in the transform window, then a ton of samples will not make a huge difference. But if your transform window just has a few specks in it, and your preview image is grainy, you can be pretty sure your going to need a lot of samples to get a good image.
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terrypin
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« Reply #9 on: August 20, 2007, 05:10:38 PM »

Lycium, Don:

Thanks both, appreciated. But I have to say the penny remains undropped. The key point I don't get is what Apo is doing for 3-4 minutes, if all it delivers is a 1.3 MB image? Don, assuming yo have Apo, Could you take a few minutes to try the example I gave please.

--
Terry, West Sussex, UK
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terrypin
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« Reply #10 on: August 20, 2007, 05:15:10 PM »

Just registered here with the aim of asking some very basic questions. But at first sight I don't see any appropriate forum.

Basic questions concerning the use of a particular fractal rendering application would fall under the "Fractal Software" category, either under the "Help & Support" board or the "General Discussion" board.

Thanks. Looks pretty quiet in there, and it probably makes sense to play out the thread here this time.

--
Terry, West Sussex, UK
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doncasteel8587
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« Reply #11 on: August 20, 2007, 09:28:19 PM »

Don, assuming yo have Apo, Could you take a few minutes to try the example I gave please.

I looked back through the thread, and didn't see an example?

It's not the size, it's the quality. The image size is dictated by the number of pixels and the image format (bytes/pixel)

A crappy image 640x480 is going to have roughly the same file size as a high quality 640x480 image of the same image format.
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lycium
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« Reply #12 on: August 21, 2007, 05:23:59 AM »

I looked back through the thread, and didn't see an example?

it's a link from an above post, here duplicated: http://www.fractographer.com/test3/temptress%20fullsize.jpg (37mb, resolution is 13468 x 8428 so when not viewing pixels 1:1, use something that does resizing right, like irfanview, or it'll look poo!)

It's not the size, it's the quality.

it's actually both wink

A crappy image 640x480 is going to have roughly the same file size as a high quality 640x480 image of the same image format.

not true at all... images with lots of noise have much higher entropy (information content,  la shannon) and therefore don't compress as well -- you can try to force it with a format like jpeg to have the same filesize but then the image quality will be considerably lower.

btw, images with sharp features are by far more needing of antialiasing than ones with mostly smooth colour ramps. aliasing looks horrible! http://en.wikipedia.org/wiki/Aliasing
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« Reply #13 on: August 21, 2007, 06:12:10 AM »

It's not the size, it's the quality.

I have been told this is true in many circumstances.    wink   cheesy    grin

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lycium
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« Reply #14 on: August 21, 2007, 06:18:57 AM »

It's not the size, it's the quality.

I have been told this is true in many circumstances.    wink   cheesy    grin

eep, are we really going to head down that avenue of discussion?


with regard to image quality, resolution is certainly of importance because no matter how well rendered the pixels are, if it isn't at or greater than the desired resolution (say, for a desktop wallpaper) then interpolation will be required, massively degrading the quality of the result.

as a concrete example, i use a widescreen display which has an aspect ratio of 16:10. the largest such display (as far as i know) has resolution 2560x1600, thereafter is the 1920x1200 resolution at which i release my images. now, if someone releases a wallpaper at 2560x1600, it's no problem for me to do a high quality resize to 1920x1200 for my desktop. however, the images i release at 1920x1200 will have to be interpolated to 2560x1600 which won't look very good.
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