jagged parrallel edges

[bisenberger]

Hi,
I have a model with 3 sets of stairs. The parallel edges of the stairs render very jagged with V-Ray. I can't seem to find the setting to make the parallel edges render smoothly. Any help would be appreciated.

[Morbid Angel]

well its a typical case of a anti-aliasing and filtering. To get smoother edges you need to increase aa samples and also work with your image filter, try a more softer filter like quadratic, or soften with low value.

[bisenberger]

Morbid Angel, I set the Image sampler to Adaptive DMC, Antialiasing filter Quadratic, Adaptive DMC image sampler Max subdivs: 100. The stairs look different, but not any better. The other edges in the image look fine, it's just the parallel edges of the stairs.

Here's the 3ds max (verions 9) file if you want to have a look.

[bisenberger]

The only real success I've had is increasing the resolution of the render, but it still doesn't look right.

[jensl]

I've run into this issue too. I've gotten the best/fastest results by rendering double resolution with a soft filter over native resolution with tons of samples, but it's a common issue with a limited number of pixels representing a lot of detail.

[joconnell]

You're not going to get it unfortunately - whats happening is you've got a line going at a very slight diagonal to a line of pixels in the image - the line you've got is crossing over small parts of pixels, it might only be a third on a pixel and two thirds on the pixel above - for example rotate your camera so the line is more like a 45 degree diagonal and re render - it'll probably to a better job of it. Having lines like this that are at small angles will always cause problems due to how much detail you can fit in the image. You're right about resolution too - increasing this will make the pixels smaller relative to the image, and smaller pixels mean finer anti aliasing.

[bisenberger]

Thanks for the info I appreciate it

[Jer25]

I think you may have overlooked the filtering options. I don't think quadratic is your best option but I could be wrong. If you look at the very bottom of this page the info there might help. http://www.spot3d.com/vray/help/150S...ge_sampler.htm

Good luck

[^Lele^]

As John said, moire is something you will experience even in real photography or film, it's all down to the actual resolution of the image, versus the detail resolution.
There is no filter that will just make it right, if the conditions won't allow it: smoothing filters will basically just blur the detail, which you could as well do in post.
Raising the max subdivs for the AA won't necessarily solve it, as the samples will be shot if the difference in adjacent pixels is bigger than the noise threshold.
You may try to get rid of them by raising the min subdivs, forcing vray to take more samples per pixel before the AA filter kicks in.
Indeed, there is no guarantee of a solution, bar maybe making the details slightly off-scale (deeper/taller steps) to allow for more pixels per step.
Maybe not architecturally correct, but if the goal is a good image for that one shot, you may want to trade accuracy for beauty

[TRGraphics]

I have noticed that extreme contrast plays a part as well on horizontal lines and aliasing. The contrast between the lit area and the dark shadows in your image probably have a something to do with it.

I sometime render the irrmap without textures, light grey color, and then render with the texture or color, using the saved irrmap, and it helps. But in the case of your image, it looks to be that the shadows a way to dark.

[^Lele^]

The contrast between the lit area and the dark shadows in your image probably have a something to do with it.

Of course it has. That's when vray checks for the so called noise threshold.
More contrast, more samples, so to speak.