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HD details in IRay

marblemarble Posts: 7,500
edited May 2016 in The Commons

I am confused about how to get IRay to render HD details. I read in another thread that IRay requires the Render Time Subdivision level increased but when I do so (to level 4) it makes no difference. Increasing the "plain" SubD level makes no difference either. I'm using Zev0's HD aging morphs for G2F.

Post edited by marble on

Comments

  • Oso3DOso3D Posts: 15,085

    I think one problem might be lighting; second image looks very diffusely lit. Try adding a spotlight up and right.

    Also, make sure to change render settings/filtering/pixel radius to, oh, .5 to have sharper details.

     

  • marblemarble Posts: 7,500

    It was my own stupid mistake. I did not have the figure selected when I was playing with the SubD settings (probably had a camera selected or something silly). So I can confirm that SubD in the Render Time slot renders the HD. I now need to play some more to find the optimal setting as I believe SubD comes at a VRAM cost.

    I'm also interested to know what thos filter settings actually do, Will.  This one has two spotlights and the HDRI dome on - it looks a little sharper to me. Pixel radius to 0.5 as you suggested and I changed to Lanczos rather than Gaussian but can't see that it made much difference.

    MeMoo Asian.png
    1600 x 1600 - 3M
  • Oso3DOso3D Posts: 15,085

    As I understand it (and I might not), basically the pixel radius adds a Gaussian blur as you render, to help cover up fireflies and other defects.

    I find that makes things a little too blurry at the sizes I prefer and then end up having to do Sharpen, so nowadays what I do is render double size at Pixel radius .5 and then shrink the image, which, I think, ends up with a pretty nice image.

     

  • marblemarble Posts: 7,500
    timmins.william said:

    As I understand it (and I might not), basically the pixel radius adds a Gaussian blur as you render, to help cover up fireflies and other defects.

    I find that makes things a little too blurry at the sizes I prefer and then end up having to do Sharpen, so nowadays what I do is render double size at Pixel radius .5 and then shrink the image, which, I think, ends up with a pretty nice image.

     

    Good tip though what do you do to shrink it? Just use an image editor like Gimp or PS? 

    I noticed that at 0.5 I was gettng some jaggies on the high contrast edges - I'll tweak a bit more.

  • SpottedKittySpottedKitty Posts: 7,232
    marble said:

    So I can confirm that SubD in the Render Time slot renders the HD. I now need to play some more to find the optimal setting as I believe SubD comes at a VRAM cost.

    Very much so — each "step" of SubD will, generally speaking, quadruple the memory needed to hold the mesh data for that object. This is why having the SubD too high on too many figures will drastically slow down any except the most powerful computers, and in extreme cases, might crash D|S. You might need to reduce the Texture Compression threshold settings to compensate, but be aware this might reduce the render quality.

    Incidentally, I usually go by the rule of "if the HD morph is starting to be visible in the Viewport, the setting is high enough to render acceptably well in Iray". A bit of a rough rule of thumb, but that gives me a starting point to begin tweaking in earnest.

  • marblemarble Posts: 7,500
    SpottedKitty said:
    marble said:

    So I can confirm that SubD in the Render Time slot renders the HD. I now need to play some more to find the optimal setting as I believe SubD comes at a VRAM cost.

    Very much so — each "step" of SubD will, generally speaking, quadruple the memory needed to hold the mesh data for that object. This is why having the SubD too high on too many figures will drastically slow down any except the most powerful computers, and in extreme cases, might crash D|S. You might need to reduce the Texture Compression threshold settings to compensate, but be aware this might reduce the render quality.

    Incidentally, I usually go by the rule of "if the HD morph is starting to be visible in the Viewport, the setting is high enough to render acceptably well in Iray". A bit of a rough rule of thumb, but that gives me a starting point to begin tweaking in earnest.

    So far I have not ventured above Render SubD at +3 and even then, only for close-ups with only two characters in the scene. Things like Zev0's Ageing morphs and Vascularity have parameter dials which can make them stand out even at +2. I thought the Viewport required the other (plain) SubD to show the details - I'm not sure I've seen HD in the Viewport with just Render time SubD but I'll have a look later.

    Where are the Texture Compression settings and how does the threshold work? I'm still so new to IRay.

  • marblemarble Posts: 7,500

    I just did a little test using GPU-Z. I loaded a G2F (V6) character (including hair but no clothing) with added V6 HD morphs plus Zev0 Vascularity. I set the Render SubD to +3 and hit render and I could see the vascularity, etc. GPU-Z reported Memory at 1536 MB. I then dropped the Render SubD to +1 and tried again. Obviously, all sign of the HD morphs had now gone but the GPU memory only dropped to 1490 peak. So not such a big hit as I expected.

  • mjc1016mjc1016 Posts: 15,001
    marble said:

    I just did a little test using GPU-Z. I loaded a G2F (V6) character (including hair but no clothing) with added V6 HD morphs plus Zev0 Vascularity. I set the Render SubD to +3 and hit render and I could see the vascularity, etc. GPU-Z reported Memory at 1536 MB. I then dropped the Render SubD to +1 and tried again. Obviously, all sign of the HD morphs had now gone but the GPU memory only dropped to 1490 peak. So not such a big hit as I expected.

    Do it the other way around...go with the low settings first.   The way memory is allocated/reserved you may not be getting an accurate reading by starting with the higher level first.

  • SpottedKittySpottedKitty Posts: 7,232
    marble said:
    Where are the Texture Compression settings and how does the threshold work? I'm still so new to IRay.

    On the Render Settings pane, click on the Advanced sub-tab right at the top (normal default setting is Editor). I've never gone into this myself, but if it works the obvious way, the only thing you should avoid is bringing the High Threshold value below the Medium Threshold value.

    I'd point you to the manual page in the wiki, but that bit's still blank. 

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