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Turner
02-21-2004, 09:13 PM
All things being equal (to the best of my ability) I rendered a tiny scene of four platonics* on a small plane using the same HDRI background, one in Carrara Studio and one in Lightwave; the Carrara render took 9 seconds, the Lightwave render, 27.

So... I'm looking for tips to improve rendering speed - AA was set to Medium to get it to look the same as the Carrara on "Quick".

Thanks

*Ladies and gentlemen! The Platonics!

fabmedia
02-22-2004, 12:49 AM
Use Interopolated. Depending on the size of your scene try non-cached, 7x21, .232 and 100mm to start. You also need to turn on motion blur, perferably dithered and set to either medium or high. You'll achieve reasonably good results, but of course you'll need to adjust for better quality as needed.

Cheers!
Arlen

toby
02-22-2004, 01:20 AM
Is Carrera real radiosity? If you set a bright red object next to a white object will you get red bleed on the white object?

I believe it's more comparable to Lightwaves 'Backdrop only' radiosity, try that - it's much faster. If you set it to 3x9 and turn on motion blur you'll have great, fast results, but not quite as accurate as Interpolated or Monte carlo.

here's a tutorial on fast HDRI

http://www.hades-studios.com/hdritutorial

Turner
02-22-2004, 05:38 AM
Carrara's radiosity is the real deal - I posted a few (rudimentary) shots for reference:

http://www.turnerdesign.net/render

See rad1, rad2, rad3, which took 10 seconds, 25 seconds, and 28 seconds, in that order. Rad2 has an HDRI wrap and "medium" light quality, but all other settings are on default (low quality).

BTW, thanks for that link - pretty interesting. I'd like to try the same scene in Carrara - is there a way in LW to select all polys with 4 vertices and tesselate them into triangles?

Cheers
Andrew


Originally posted by toby
Is Carrera real radiosity? If you set a bright red object next to a white object will you get red bleed on the white object?

I believe it's more comparable to Lightwaves 'Backdrop only' radiosity, try that - it's much faster. If you set it to 3x9 and turn on motion blur you'll have great, fast results, but not quite as accurate as Interpolated or Monte carlo.

here's a tutorial on fast HDRI

http://www.hades-studios.com/hdritutorial

fabmedia
02-22-2004, 09:56 AM
Okay, I seem to be talking a lot lately about LW render engine. It is 192 bits. Everyother render engine on the market is 128 bit. Naturally LW is going to be slower. In short, there's a lot more data AND is more accurate.

Arlen

Turner
02-22-2004, 10:03 AM
Ok - but suppose I'd like to "sacrifice" those 64 bits for faster, less accurate rendering - can I?

Quite honestly, as I'm just starting out and not really noticing "inaccuracies" in my other renderers that can't be smoothed out by simply raising the various aspects of image quality (e.g. more accurate shadows) I don't get much out of those extra 64 bits - that I know of.

Andrew


Originally posted by fabmedia
Okay, I seem to be talking a lot lately about LW render engine. It is 192 bits. Everyother render engine on the market is 128 bit. Naturally LW is going to be slower. In short, there's a lot more data AND is more accurate.

Arlen

toby
02-22-2004, 12:48 PM
Originally posted by Turner

BTW, thanks for that link - pretty interesting. I'd like to try the same scene in Carrara - is there a way in LW to select all polys with 4 vertices and tesselate them into triangles?


press 'w' for the stats window, click the '+' next to '4 vertices' while in polygon mode - that selects them - then hit shift 't' to triangulate them. Does Carerra only accept triangles?

Nice images! I guess Carrera is a little more serious than I thought - I really like the dof-test one.

LW's radiosity was one of the first commecially available renderers, it's been around for more than 4 years - probably why it's slower than others.

I'm working on something with Backdrop radiosity - this is 138k polygons, enhanced medium AA, raytrace reflection and refraction, 30 min. on my old G4 450 dual. All illumination except for the orange highlight is from the backdrop color.
http://www.tobygaines.com/benz3.jpg

Turner
02-22-2004, 05:48 PM
Nice car!

And that polygon count.. Yikes! I haven't built or rendered anything that massive yet. Nice work.

Andrew

toby
02-22-2004, 05:56 PM
Thanks!
138k is nuthin', there are guys here with over 2 million - some higher

RUdiger
02-22-2004, 11:58 PM
Okay, I seem to be talking a lot lately about LW render engine. It is 192 bits. Everyother render engine on the market is 128 bit. Naturally LW is going to be slower. In short, there's a lot more data AND is more accurate.

Actually the other renderers will be 24- or 32- bit compared to LW's 96- or 128-bits (depending on whether we count alpha).

You can't see much difference because noone has a display that can generate much more then 24-bit color. You could see that extra depth become useful by scaling the images up. 24-bit renders will show banding and other depth problems from being scaled up. Floating-point depth pixels can be scaled up alot more without running into artifacts caused by the lack of actual information in shallow pixels.

toby
02-23-2004, 02:32 AM
Applications that are only 32 bit can't use or output HDRI, and can't even have light and luminosity values above 100%. Like in Electric Image, try to move the camera in a space scene: motion blur smears the stars to dark grey, and there's nothing you can do about it.

fabmedia
02-23-2004, 10:03 AM
LW renders @ 192 bits. This is because the information that is contain in a Floating Point image contain everything you need for an HDR image. LW is the only render engine that can do this. Now whether you save it as a 192 bit image is up to you. But whether you can see all of the image on the screen doesn't matter, it's what extra information is being held within the image is what counts. This is the main reason why LW renders take longer.

Cheers!
Arlen

Turner
02-23-2004, 10:31 AM
"But whether you can see all of the image on the screen doesn't matter, it's what extra information is being held within the image is what counts."

Not really. What counts is whether or not the output you get is what you need; I ask again, can we disable the "extra" information if we don't need it?

If not, then my question is, why not? Sure, I might need 192 bit rendering at some point - but I'd rather that option be left up to the user, since whether or not I see "all of the image" on screen doesn't really matter if I can't get my rendering done on time.

I don't need a trailer hitch if I don't have a boat.

Just saying.

Cheers,
Andrew

fabmedia
02-23-2004, 11:02 AM
Yes I know what you mean. Why? Well... ya gotta ask Newtek. Maybe and hopefully that is what Worley's FPrime is doing. Giving us that option. Damn quick it is.

Arlen

toby
02-23-2004, 02:26 PM
There's just too many possible options like that for them to implement all of them.

Also I think the bit-depth would be very hard to change, maybe requiring a second renderer - but I still think that the radiosity hasn't been optimized, there's several features that other renderers have that save time, like being able to 'add to' a radiosity solution, and being able to manually concentrate rays in areas that you want, giving you higher quality only where you need it, and settings that 'smooth', just like what we're doing with motion blur.

fabmedia
02-23-2004, 02:56 PM
I agree with you. I don't know if I would change the bit depth, but I like the thing having to do with the concentration of rays in selected areas.

Apparently scan line renderers are faster, but I'm not too sure about that.

What do mean by "add' to a radiosity solution? And I've never heard about smoothing. Isn't that the same as what's under the render panel?

Arlen

Lightwolf
02-23-2004, 03:10 PM
Sorry for jumping in...
I see these 192 bits spread around a lot.
Now, if we assume NT mean RGBA, we would have 48bits per channel, which doesn't make sense, floating point numbers are either 32 bit (float) or 64 bit (double) (well, they can be 80bit too, but that is rarely used).
If you look at the SDK, you'll see that LW uses 32 bit floats for image buffer, which means that 128 bits out of those 192 bits are for RGBA. That leaves us with 64bits, which is probably a (double) Z-Buffer, or a (float) Z-Buffer
and something else.
LW can actually use more bits if you use the 4 special buffers provided for you in the surfaces panel.
Cheers,
Mike - whe who has read the SDK ;)

toby
02-23-2004, 07:17 PM
Originally posted by fabmedia
I agree with you. I don't know if I would change the bit depth, but I like the thing having to do with the concentration of rays in selected areas.

Apparently scan line renderers are faster, but I'm not too sure about that.

What do mean by "add' to a radiosity solution? And I've never heard about smoothing. Isn't that the same as what's under the render panel?

Arlen

Adding to a solution - only recalculates radiosity in areas where things are changed

Smoothing is not the right term, I just forget the right one - basically averages out blotchiness.

MacDude
02-26-2004, 09:56 AM
Isn't it called 'Shading Noise Reduction'?

toby
02-26-2004, 10:53 AM
no, that just reduces graininess