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 Subject: Keyshot VR like renders in Maya...

Myselfsama opened this issue on May 04, 2013 · 4 posts

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  Myselfsama () ( posted at 11:47AM Sat, 04 May 2013 

Hello there, I have a model I made that I'm trying to do render a 3D turntable of but I dont have the proper know how to do it in maya.

The effect I'm trying to go for is... like can be seen here

http://hazardousarts.deviantart.com/art/Spidersilk-Assassin-Wallpaper-361572207?q=gallery%3Ahazardousarts%2F827119&qo=15

That is a render from a program called Keyshot VR, but I know it HAS to be possible to be able to render like this in maya. So far I've messed wth ambient occlusion renders, I got the infinite white background and a sort of decent looking render, but its still a bit blurry, and it also just doesnt have the look that this thing has. Anyone know how I can do it? Thanks,

~M


  Modulok () ( posted at 11:59AM Sun, 05 May 2013  · @4064455

There's a lot of different ways to do this. In any case make sure to turn off
the default scene light. This is found under the render globals -> common tab.
Un-check Enable Default Light.

Here's some options, any would give you a similar look:

Option1: You could simply enable final gathering and adjust the camera's
environment attribute to be white. You can end up with a very nice ambient
look this way which includes color bleeding. You will have to tweak the final
gather point density and the number of final gather rays in the render globals
until you're happy with the look.

Option2: You could create an mib_amb_occlusion texture and map it to the
incandescence of a lambert shader. Set the samples of the ambient occlusion
texture to something like 128 or until grain is eliminated. You can get a very
nice look this way and still keep render times low. This is probably the
fastest approach.

Option3: You could use something like a mia_material_x and enable its ambient
occlusion checkbox. Set its ambient light color to light gray. With this
approach you'll have a much softer (possibly too soft) ambient look.

Option4: You can achieve this look with area lights. These take a bit longer to
render but give a very soft, i.e. photographic softbox look. For added awesome
you could enable global illumination but that will take some serious tweaking.

Option5: You could use an image based lighting approach. In the mentalray
render globals, in the indirect lighting tab click the create button next to
Image based Lighting. From there either map an HDR file to the
mentalrayIblShape node's image attribute or select 'texture' from the
type drop down box. Then set the texture attribute to a white color. This
is basically he same idea as the option1 approach.

Can you post your attempt so far? It would help us point you in the right direction.
-Modulok-


  Myselfsama () ( posted at 4:14PM Sun, 12 May 2013  · @4066371


Thanks for the ideas Modulok! Ive been messing with it on my own until I just remembered I'd posted something here. The attached pictures is actually a lambert sphere, on a plane that has had a surface shader with mib_amb_occlusion applied to it. It caused the plane to become perfectly white except where the sphere is near. Using a sphere to create the set up because I want lower render times for now. However! I'm using like 30 some lights all set very dim like 0.05 dim, and are in a perfect circle around the sphere. The issue right now is the render time, when I tested my model in place of the sphere it not only took a very very long time, but it just didnt look great. I'm gonna remove the lights and try other lighting methods to reproduce this soft effect, but lower render time hopefully. I'll follow up with more testing. :)


  Modulok () ( posted at 3:13AM Mon, 13 May 2013  · @4066502


I rendered a 120 frame turn-table animation of the Stanford Bunny using the

techniques outlined below. Total rendertime was around 10 minutes. (This will
vary by machine and image resolution of course.) This is the technique I used:

Initial Setup

  1. Render Globals (mentalray) -> Indirect Lighting tab -> Environment. Click
    Create next to Image Based Lighting.

  2. In the Attribute Editor under mentalrayIblShape1 set Type = Texture.

  3. Set Texture color to white.

  4. Render Globals (mentalray) -> Indirect Lighting tab -> Final Gathering. Turn
    on Final Gathering. Set accuracy to around 300. If you get splotchy results
    you'll have to increase this. Increasing this increases render time so be
    careful. Set Point Interpolation to around 30. Higher values smooth the final
    gather out at little cost. Try to increase this before increasing the
    accuracy.

  5. Render Globals (mentalray) -> Common tab -> Render Options. Turn off
    Enable Default Light.

Background Setup

  1. Create a maya 'Use Background' shader. Apply this to the ground plane.

  2. In the Attribute Editor for 'useBackground1', set reflectivity to 0. This
    will give you the all white look, but will still interact with the final gather
    diffuse shadows.

Final Gathering Accumulation

Final Gathering is gorgeous but render intensive. We want the soft look but not
the long render times. Because we're rendering a turn-table animation we're in
luck! We can tell mentalray to accumulate final gather results to a file for a
few camera angles and then re-use that data for all subsequent renders. As long
as we don't move or animate our model (I animated the camera using a NURBS
circle as a motion path and a simple aim constraint) we are free to re-render
from any angle and mentalray will use the pre-computed Final Gather. This can
reduce render times by a multiple of 10.

  1. Do a test render, tweak your shader colors, and render globals until you're
    satisfied. The renders will be slow because we're computing Final Gathering for
    every frame.

  2. When satisfied with the result and ready to render your turn-table sequence,
    return to the render Globals (mentalray) -> Indirect Lighting tab -> Final
    Gathering -> Final Gathering Map. Set Primary Final Gather File to any name.
    (Mentalray will create this file at render time in the current project
    directory. I called my 'fg'. You can name it anything.)

  3. Set Rebuild to 'Off'. Re-render the scene from a few different angles
    around your model, front, back, right side, left side, etc (perhaps 5-6 frames
    equally spaced around the model.) This will accumulate results to the final
    gather file. Whatever you do, don't animate your model! (I animated the
    camera.) You can speed this process up by turning down anti-aliasing to
    extremely low quality (like 1 sample every 16 pixels). At this point we're only
    interested in computing Final Gathering, a jaggy render is not a problem.

  4. When done with your 3 or 4 accumulation renders, set Rebuild to 'Freeze'.
    Subsequent renders will only re-use the stored final gather data points and
    will not have to compute them at render time. The savings in render time can be
    a factor of 10. Render your turn-table sequence. (Remember, animate the camera,
    not the object.)

Just remember to set Rebuild back to 'on' if you change the position of your
model and then re-do your 4-5 Final Gather accumulation renders. Otherwise you
will see a dark splotch where your model used to be and the Final Gather points
will not match the illumination in the scene. (It looks funky.)

Other Thoughts

If you have a workstation graphics card, such as an Nvidia Quadro card you
could instead render an ambient occlusion pass directly on the GPU using Maya's
Hardware 2.0 render. If tweaked the results can look pretty good, though not
as nice as mentalray. (Unless you're using Maya 2014 using the new directX
shaders.)

Good luck!
-Modulok-


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