I know I must seem a little naive at this point, after all is some yrs that I Bryce, but there was this topic in my head that every now and then returns...

So here it is:.

there's a way to know in advance the time of render on a scene ?
I mean, I thought I could render a 200x100 picture or so AND by comparison, say, to render a 2000x1000, it could require ten times the 200x100 render time...

Is that simple or am I forgetting something ?

BTW, seems that the renders are far more longer than that, if I calculate in this manner.
What's wrong with this approach ?

Any other means of ETR... ?

doesn't work out that way.. can't times it..
in bryce..on the left hand side of the window..where the render options are.. there is this report time .. tick that..
more rays needed per pixel..if me making sense here..or remembering rightly.
the others can add to it..
all i say for renders that have things like glass and water and large.. go take a holiday and get back..
cheers

• rosie

Well its more then 10 times because:

•  200x100 = 20000 pixels to render

•  2000x1000 =  2000000pixels to render

•  2000000 / 20000 = 100 times as many pixels.

Also bryce does some optimalizations on rendering, and textures or reflections might turn out more or less difficult to handle for AA etc. on specific resolutions. So its never really a sure thing. Like rosie says, the amount of rays per pixel also makes a difference to the render times.

Also i would speculate that it might be possible that normal AA mode uses a dynamic amount of rays per pixel to reduce rendertimes by using less rays for less AA intensive areas of the image and more rays when more are required for more AA intensive areas of the image. Or at least, thats how some other apps on the market handle their AA.. so it might be that bryce does so as well... 

Rayraz beat me to the error in your math.  I have not been able to find an accurate way to estimate the time but for me, using regular AA and rendering to screen, I can get a relative approximation by looking at that render timer on the lower left the screen after the first pass then double it.  If it says 1hour time remaining then it will probably take closer to 2 hours for finished render. Cheesy, I know.

If you render to disk you cannot use simple deduction like 10% rendered means 10% time elapsed. Your scene may be 10% rendered down the page but it hasn't even hit that glass, soft shadowed, volumetric yet.  That is when everything slows to a crawl.

Correct me if I am wrong, anyone.

I use this technique, mainly when rendering glass and/or using HDRI/IBL lighting, as Bryce seems to lie to me on estimating render times for those kinds of scenes, lol.

The technique is not perfectly precise, but it should give you a very good ballpark idea on whether or not your full sized render will take 2 hours....or 20 hours.  ;o)

AS

Wow, new avatar, a very flattering picture that, Erosiaart...;)

Volumetric anything will also slow things down considerably.

Bryce has a minute hand, an hour hand, and an eon hand - They might be giants, Particle Man...;)*

Thanx Agent Smith , I think I understood the flaw in my original statement...  If I may call for some additional info, do this means of calculate ETR include Render to Disk too... ??

pakled..thank you.. i know I'm cute and adorable and all things sweet . :-p :-p
AS..never thought of calculating it that way.. good idea.. but yup.. if you render to disc.. would that also work? Since Bryce renders at 72 dpi,  the amount of dpi chosen to render to disc affect the timings, the inevitable being if you choose 300 dpi.. of couse one would expect the render to take more timings...

 A higher DPI only takes longer to render if the amount of pixels also increases.

DPI only describes how densely the pixels get distributed once the image gets printed.

800x600@72dpi has the same amount of pixels as 800x600@300dpi.

DPI works much in the same way that putting a higher screen resolutions on your monitor, allows you to display more detailed images on it. If you put an 800x600 image on a monitor at 800x600 resolution, it'll fill the screen. If you put the same image of 800x600 on a monitor at 1600x1200 resolution, it'll appear smaller, because its pixels get packed more densely onto the screen.

The only difference between 300dpi and 72dpi is that (unless you explicitly tell your printer otherwise) it'll print out the 800x600@300dpi smaller, then the 800x600@72dpi, because it packs the pixels more densely on the paper. Similarly as setting up a computer monitor at a higher screen resolution

As Rayraz states perfectly;

"A higher DPI only takes longer to render if the amount of pixels also increases"

In my book, dpi just doesn't matter, because I render everything to be 300 dpi, since that is basically THE standard for any kind of printing, just about everywhere on the planet.

For example, if I were to create a new document, and I knew I wanted to render out to fit perfectly on a u.s. 8.50" x 11.00" piece of printer paper, I actually have that size memorized, in pixels, which is 2550 x 3300.

Render To Disk and Estimating the Time of Render;

Yes, this technique will also work if you are going to Render To Disk.

BUT...

If you are going to do a final, large render and you are in fact going to Render it To Disk, you MUST also render your small test Render to Disk ALSO.

If you don't, the estimate will be way, way off!

(Because from my tests, Rendering to Screen is much, MUCH faster) (approx. 3x faster)

AS

3x faster  - (not always that much faster, but yeah, sometimes) Might have to do with my video card? (I have a fairly great one these days)

Whatever, lol.

But, point is;

If your final render will be done on-screen, then do your small test render on-screen also.

or

If your final render will be rendered to disk, then do your small test render to disk also.

 kinda weird that render to disk is that much slower.. :-/

Just tried it....only happened with one scenefile of mine.
Used to happen more often.
But, then again, its been many years since I have used Render To Disk.

My terror using the onscreen render is that I lost the job for long time renders for accidents like blackouts or some PC screwup, so I do prefer at all times Render to Disk... and it seems quickier too... but that's definely a graphic card issue, I think...

Yeah, got to be.

I have a Nvidia FeForce GTX260, it pretty much laughs at anything I can throw at it.