Hi guys!

I don't know if you already tested this idea; it saved my latest pic (see link) which was impossible to render in a normal way (due to some unknown problem the rendertime on the final render/low AA settings skyrocketed to over 160 hours) so I did the following: I set the render to "Preview" and the size to about 2500 x 2XXX pixel instead of 800x600 with normal AA.

http://www.renderosity.com/mod/gallery/index.php?image_id=1247153

When the rendering was finished after 1,5 hours, I opened the the large pic and resized to a smaller format (back to 800 pix.); to my amazement the image was almost perfectly antialiased after resizing!

It seems to be an effective way to dramatically cut down rendertimes and still obtain an antialiased pic. 

Yes, I was aware of this trick, but never tried it before. what cropping method did you use? Bicubic or bilinear?

I used the "Bicubic" setting; I didn't experiment with that; maybe one can further improve the resize result using different resampling methods. 

1. Hm, using "Bicubic Sharper" gives the best result; I wonder if I ever will use final AA renders in Vue... :-)

Gotta give it a try.

Thanks for the tip.

you rendered at preview?  That is pretty impressive for a resized preview.  When I have used this technique I have used custom settings, but loaded broadcast settings and removed the AA.  Seems preview settings are plenty good enough!

Thanks

Yes Rich, I did! The only case it doesn't work is when you preview render trees/ecosys with trees; the leaves won't look great when you resize but otherwise it'll be OK. 

I think preview won't work for reflective and materials that have variable transparency either, because preview doesn't compute these effects well enough. I'm trying rendering a scene now in "user settings", with my high render settings, but without AA, and I'll see if the result looks right. I have soft shadows on, and if this trick works on soft shadows, that would speed up render times a lot.

Thanks bruno; let us know what result you did get using this shortcut! :)

Well, I'm posting the result in the gallery now, it's called Clear waters.

I'm not sure this was the best test , since I have a proc terrain, an ecosystem, water, soft shadows and GI;, rendered at 1800x2400, and it took 24h to render without AA.

I must say that the result is absolutely convincing, and my soft shadows are not noisy.

Now I wonder what would've been the render time with my usual AA settings, but at 800x1200.

Guess this is time for another test!

I've been rendering very large (over 4kx3k) without AA for my last several renders.  It turned out just fine.  I've been using "weighted average" on the downsizing in Paint Shop Pro X.   Is bicubic better?

Pretty good result bruno on your latest although the rock texture seems a bit blurry for me but nothing disturbing; this trick is clearly a life saver when one get unacceptable render times(more than 30-40 hours) with normal AA.

Matrixmode: Bicubic/Bicubic Sharp resizing gives the best result imo.

Thanks attileus!  Gonna go back and redo some images.  :)

Attached Link: Render test.

Reflections and fine texture details turned out okay though. Nice way to cut down rendering time dramatically.

Hm, I'm not a Vue/Photoshop expert and I don't know your Vue Atmo/GI/GR settings on your excellent testrender; in this case I would go for a higher GI/GR quality (almost maximum) and also set the shadow quality for the highest...but of course the rendertime will increase again even in "Preview". Let us know if this helped! :-)

Attached Link: Second test

I used 4 default texture types with HDRI. Light/atmosphere was stock settings. It seems transparency and reflections was handled well on the preview render setting. Original image was 3000 X 1688 and downsampled to 800 X 450. Obviously, you'll need to scale up if you need a bigger downsampled image.

For the shadows, you were right. Increasing the light/shadow quality does help alot. You don't need to do it if you're using "busy" textures for the surroundings. Maxing up the settings jacked up the render time abit but it's still significantly faster than a final setting render. So I guess you can go crazy on the quality settings if you're planning on rendering with preview.

Post was done with CS2, resized with bicubic sharper. Converted to Lab mode and unsharp mask on the lightness channel. If you skip the second step, it'll look more anti-aliased but I wanted to test the texture details here.

Many thanks wakrased for your extended test; it's good to know that one can increase the Atmo settings without too much rendertime!

I don't think preview is appropriate when you have reflections, soft shadows and other advanced effects , but using user settings without AA should look good.