Sharp wall edges/corners in room: How?

[skogzort]

Hello,
Almost every VRay render I see has nice sharp edges/corners where walls meet and where the ceiling/floor meets the walls. Like the first photo here: http://www.chaosgroup.com/forum/phpB...ic.php?t=19050

I am working on my first “room” rendering and I can’t get the edges/corners to be sharp. I’m using VRay Sun + VRay sky with IR for primary and QMC for secondary. (I tried LC for secondary, but ever render was over bright and lost too much shadow density- probably because almost everything in the scene is White) There are no textures/materials and everything besides the basic structure and pool is hidden. Sometimes I added a VRay light/skylight portal at the big window, which increased the shadow density a little, but messed up the GI tint and did not help the sharpness of the corners/edges.

These are some of the IR map settings I’ve tried so far:

1)min-3 max 0/ HSph subs 50/ least squares (7min)
2)min-3 max 0/ HSph subs 75/ least squares (12min)
3)min-3 max 0/ HSph subs 75/ least squares + detail enhancement (34min)
4)min-3 max 0/ HSph subs 75/ least squares + lower Clr.Thresh to .15 (1hr 12min)
5)min-3 max 0/ HSph subs 75/ delone (11min)
6)min-3 max 0/ HSph subs 100 / delone (40min)
7)min-3 max 0/ HSph subs 100 / delone + rQMC subs 2.0 (1hr 16min)
min-3 max 1/ HSph subs 75 / least squares (24min)
9)min-3 max 1/ HSph subs 50 / delone (11min)
10)min-3 max 1/ HSph subs 75 / delone (24min)
11)min-3 max3/ HSph subs 75/ delone (1hr 24min)


I also tried lowering the interp samps from 20 to 10/5 but it did not seem to do much for the edges. Is it because I’m rendering at the wrong size (640X480)? Am I just not rendering long enough - should I turn up the rQMC subs and render for many hours? Is it because I’m using a 3DS Max camera? Is it the angle of the light coming into the room? Or is it my IR map settings? Is there something else I should be adjusting other then the IR map settings?

Of all the changes I’ve made so far the one the seemed to help the most was lowering the Clr. Thresh to .15, but it made the rendering take close to 6 times as long and still no sharp edges (see arrows):



Any suggestions would be much appreciated. Thanks for your time and help

[joconnell]

A big difference is changing your anti aliasing filter too - the default of area is a little blurry and looks a lot more like a max render. Try mitchel netravelli or catmull rom and you'll get a far crisper look. That said, catmull edges are very harsh and can lead to some problems if you do a lot of colour correction on your renders in photoshop or after effects. You can get a similar look by applying the unsharp mask filter to a render in photoshop.

[Neilg]

What wont be helping is having the same material on the wall and floor. Get a bit of colour on the floor, some subtle vraydirt within the material, take off your AA filter and re-render.

A sharpening filter wont do all that much for you there because of the materials blending into each other, create some distinction between them and it'll have a field day.

[Paul Oblomov]

Use DE (detail enh.). And you'll get everything you need. Use smth like low preset (irrmap.) with de turned on. Don't forget that de don't need high hsph. subdivs. So, in your case
hsph. 30
iterp. samples 30
de - on
radius 10 (default screen mode = that mean 10 pixels will be the area, where QMC will be used instead of irrmap)
subdiv mult. 1

And that's it

[DaForce]

What type of material do you have on all the mesh? is it a white vraymaterial? white is rather bad for testing stuff like that. go with a medium grey, or better still but some color onto the walls.. as cubiclegangster mentioned.

[skogzort]

Thanks for all the help. I tried every suggestion and then some. What ended up working best for me was to just slightly change the color of each: wall=white 225, ceiling=white 215, floor=white 220. Also I will add a molding to where the floor meets the wall. This is what I decided was good enough for now:




DaForce - I was using no aliasing for any of the renders.

[brian451]

I can't tell you how much i have to disagree with using such high ir map settings. Even for a highly detailed scene, which this is clearly not, you dont need anything even close to a min/max of 1/3 and h.subdivs of 75. You could get the ir map done in a fraction of the time using much lower settings.

For the intensity you're seeing outside combined with the white color of the concrete, you should be seeing much brighter light in the shadows. I would tone down the sun intensity and tweak the color mapping (Linear, Exp, or Reinhard) to get the proper relationship between direct light and shadow.

You know you could always use a vray plane light as a fill light for the shadow areas. This would makes things a lot easier for you.

BTW, if you want to see what a near perfect image for the lighting configuration you're using, try switching to progressive path tracing. When you do, you don't have to worry about image sampling, material or light quality settings, noise threshold, and numerous other things. Lot of times if its at the end of the day and i dont have time to do a lot of testing, i'll switch to PPT and max the light cache subdivs value...when i come in the next morning i almost always have a nice rendering.

[skogzort]

Thanks for the response,
I am using a VR plane light at the window as a skylight portal. I am using Reinhard CM and my VRsun is already lowered to .003. I would like to have shorter render times but if I lower the passes with Min/Max then I get no shadows at the base of the pillars. If I lower the HSph subs then all the walls become blotchy. The only control I have over the VR plane light (at the window) is by raising the VR environment skylight – which burns out the outside even more. I tried un-checking “use as portal” so I could manually adjust the light, but then the color goes way off and the shadows look really fake. If you can suggest some settings I will try them out.

For PPT what subs value would you use? To do it that way what do you use for primary and secondary bounces?

Thanks again for the info

[brian451]

to do ppt, you need to set both primary and secondary to ppt...that's the beauty of it, no more worries about ir map, image sampling, shadow subdivs, noise threshold, etc. just make sure to set subdivs really high (to a max of 65000) and turn off antialiasing...the second it starts rendering you have a rendering, but obviously you need to let it cook for a while. just stop it after the noise is reduced to your liking.

[DaForce]

assuming time is of the essence here, then PPT is not a valid option in most cases. And even with his high IRmap settings its still going to be ALOT quicker than PPT.
But your are definitly right about the quality of PPT, no arguments there.

[brian451]

assuming time is of the essence here, then PPT is not a valid option in most cases. And even with his high IRmap settings its still going to be ALOT quicker than PPT.
But your are definitly right about the quality of PPT, no arguments there.

i totally agree with you...i only use it when i gotta get out the door and/or time is not of the essence...but even a modest size scene can render fine overnight...and certainly over the weekend. even if there is noise in some areas, a few render regions can easily fill in the noise where needed

[DaForce]

Yeah definitly. But overnight and overweekend.. hehe most people need renders done over lunch

PPT is wonderfull, but not really a production tool as such.... you know.. kinda like maxwell
haha j/k

[brian451]

agreed, but for a new user struggling with quality settings, i would say it is a production option

[DaForce]

They have to learn at some point, why pospone the inevitable