berliner Posted March 19, 2010 Share Posted March 19, 2010 HI, I'm working on some high resolution renders that will eventually be as large as A4 format, so like 3000 x 2186. I'm noticing as I increase the size (haven't even gone to the A4 size yet) that there are alot of jagged edges and some artifacts showing up a bit in areas. I did however notice, that I saved them as tga files then in photoshop, if I zoomed in to the image, the aliasing wasn't so much there anymore, but the sharpness of the edges was blurry. I'm still learning how to really use FG/GI for optimum quality. Here are shots of my settings. Please let me know if you see something that looks really off, as I've already tried going up and down with them. Also, here is a region of the image I'm rendering with the roof edges showing the issues. Thanks so much for any help or comments! Link to comment Share on other sites More sharing options...
CJI Posted March 19, 2010 Share Posted March 19, 2010 Well its difficult to see the aliasing your talking about at that resolution as its not really clear. But from your settings the first thing i noticed is that you have GI on for an exterior. This is generally not required in unless its particulalry dark and you need the extra light that GI gives you. Also why are you using Radius Interpolation instead of FG points? Most of the time points interpolation is perfectly fine and i have never really had to resort to radius interpolation. with Points interpolation start at 50 and work up until acceptable. I would reduce your noise Filtering to standard as i think it will only be increasing your render time with little effect here. I would also turn falloff off as well unless there is a particular reason you are using it. It might darken your scene slightly by turning it off, up your diffuse bounces to 2 or 3. I wouldn't go higher for an exterior rendering. You could also pre calculate your final gather map at half the final resolution. This will save you overall time and have very little or no detrimental effect. See how those settings do, i hope they help. Link to comment Share on other sites More sharing options...
pixelperfectg Posted March 19, 2010 Share Posted March 19, 2010 (edited) Off topic comment: I'm not sure why, but I'm seeing more and more users increasing the Noise Filtering (Speckle Reduction) option. Why would you do that? IMHO that's a really, really bad idea. By doing so you're killing A LOT of indirect illumination information from your scene. It should be left at the default setting (standard) or changed to none if modified at all. EDIT: I see uddie/Curtis touched on this topic a bit already. I don't think it will increase the render time much, but it will certainly eliminate a lot of light from the scene. Edited March 19, 2010 by pixelperfectg Link to comment Share on other sites More sharing options...
mattclinch Posted March 19, 2010 Share Posted March 19, 2010 heres what i would change. dont understand the unnecessarily high noise reduction you are using FG bounces, when these are not used when using GI you are using a different AA spatial contrast ratio for your alpha channel? i tend to use 0.03 for all. don't understand why you are using a weight of 0.5 for your FG? Link to comment Share on other sites More sharing options...
berliner Posted March 19, 2010 Author Share Posted March 19, 2010 Thanks for the replies. I'll make these changes. I'm not so savvy on exterior renderings and am not sure how to really sharpen the scene to make it as realistic as possible...that said, I'm still concerned about the blurriness of the image- is that something to do with EV? I've got it set now at 13.5, highlights at .14, midtones at .7 and shadows 0.0. Any further advice? As far as using FG and GI together, I've been told and have read that they can actually function well together, especially for helping with indirect illumination- which it has by trial and error seemed to help. Also- when you say 'pre-calculate the FG map' what does that exactly mean? Like I said- I'm no expert on this so all these tips really really help! Link to comment Share on other sites More sharing options...
berliner Posted March 19, 2010 Author Share Posted March 19, 2010 oh- I should also mention that in conjunction with the EV settings, I'm using the daylight system with mr sun and mr sky..both set at 1 Link to comment Share on other sites More sharing options...
jinsley Posted March 19, 2010 Share Posted March 19, 2010 ... i tend to use 0.03 for all. ... sorry, a little off topic of your post again... Matt, why do you change the spatial contrast to .03 from the default .051??? Just wondering and trying it out now... Link to comment Share on other sites More sharing options...
Peter M. Gruhn Posted March 20, 2010 Share Posted March 20, 2010 As you increase the size of the render, it eventually becomes too big for Max to show full size in the render window, so Max shows it at reduced size but with plain pixel dropping rather than nice resampling. This is what you see. If you zoom in to 1:1 in the render window your image should return to niceness. Link to comment Share on other sites More sharing options...
mattclinch Posted March 22, 2010 Share Posted March 22, 2010 sorry, a little off topic of your post again... Matt, why do you change the spatial contrast to .03 from the default .051??? Just wondering and trying it out now... the spatial contrast value defines the difference in contrast required between two samples for MR to recursively supersample up to the value of the maximum samples per pixel. to quote If neighboring samples in a frame differ by more than this color value, the mental ray renderer does recursive supersampling (that is, more than one sample per pixel), up to the depth specified by the Maximum samples per pixel value. Increasing the Spatial Contrast values decreases the amount of sampling done, and can speed the rendering of a scene at the cost of image quality. so i tend to drop the values so that MR is more inclined to use up to 16 samples per pixel as opposed to 1. this gives me cleaner AA in areas that may have lower contrast, but still require more AA samples (such as white railings against a white wall) without having to ramp up to 1/64 samples which can massively slow down a render. Link to comment Share on other sites More sharing options...
jinsley Posted March 22, 2010 Share Posted March 22, 2010 the spatial contrast value defines the difference in contrast required between two samples for MR to recursively supersample up to the value of the maximum samples per pixel. to quote so i tend to drop the values so that MR is more inclined to use up to 16 samples per pixel as opposed to 1. this gives me cleaner AA in areas that may have lower contrast, but still require more AA samples (such as white railings against a white wall) without having to ramp up to 1/64 samples which can massively slow down a render. Thx for the reply, I thought I was being a little lazy on Friday for asking before researching so I did a lot of reading this weekend... I can't believe I havn't touched on this before. Definitely trying it out this week, I think it will really help get some of the finer details and edges to be more visible. Probably the trick is to find the balance between a lower value, sampling rate and render time for your machine. Link to comment Share on other sites More sharing options...
Justin Hunt Posted March 23, 2010 Share Posted March 23, 2010 sorry, a little off topic of your post again... Matt, why do you change the spatial contrast to .03 from the default .051??? Just wondering and trying it out now... I think alot of people tend to over look this setting, partly because a couple of versions ago it was suggested that there is no real benifit to changing this value as done in previouse versions (pre max9), and this stuck. I have played with this and it does help alot, of cause with the higher sampling taking place, render times do increase, but its worth it in the long run. Still quicker than increasing the min sampling. jhv Link to comment Share on other sites More sharing options...
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