Environment mapping question

Comments

• Hiro Protagonist Posts: 699

  April 2016

  I don't think you can, as far as I know. You mention setting a jpg, did you mean that these environments are literally jpgs and not .exr or .hdr files? If you are using actual jpgs then this may be the source of your problem. Jpgs are low dynamic range and not only will they look washed out, any colour in them (e.g. grass, or blue sky) will create a colour cast because the actual light source in the image (e.g. sunlight) does not have a high enough dynamic value to overpower other colours in the image.

  So you need good HDR environments, in exr or hdr formats, with a true high dynamic range. For example in an LDR image the value for pure white is 1.0 (255) which is as bright as a light can get in LDR, but in an HDR it will have a 32 bit RGB value of 8.0 at least, more likely much higher, such as 20.0. At the same time a deep blue sky or lit grass with have intensities in normal (LDR) ranges so although they still emit light the sun will overpower them and you won't get colour casts.
• mjc1016 Posts: 15,001

  April 2016

  Hiro Protagonist said:

   At the same time a deep blue sky or lit grass with have intensities in normal (LDR) ranges so although they still emit light the sun will overpower them and you won't get colour casts.

  Which is about the same as what happens in real life....a certain amount of light is reflected off things like grass...now tinted green...but the sun and sky 'overpower' and balance it.   To see the 'green' go stand at the edge of a meadow, just inside the woods...on a slightly overcast day.   That's about what that middle picture looks like...but even with the clouds, if you step out into the open, it will lose a lot of that green tint.   A light overcast will limit the dynamic range of the light, but no where as much as jpg does.
• Ruri Posts: 50

  April 2016

  Hi hiro, Mjc, Thanks for the explanation. Will render again with the hdr file instead of the jpeg. Anyway, I suppose there is no way to use a hdr as dome and another as light. I just have to find and use a well balanced one then.
• mjc1016 Posts: 15,001

  April 2016

  No...but it would be nice.
• Ruri Posts: 50

  April 2016

  I think I read some thread that says there is a trick to put a dome, which by default will block the light, but the method allow environment light to go through, so you somehow get a workaround. I will update here if I manage to find the post. But anyway I think just finding an environment map that works is good enough to start off.
• FirstBastion Posts: 8,049

  April 2016

  Your second image posted with the trees,  look fine for outside the window,  but you should probably turn the light fixtures inside the room itself into light emitters at the ceiling to balance out lighting of the scene on the female. That should remove the green hue.  If there are no fixtures at the ceiling, add a plane primitive pointed down to emit light. 
• Ruri Posts: 50

  April 2016

  Hi firstbastion,

  Tested it out with your advice. It doesnt come with a ceiling so I just threw a 45 degree plane with 6500k lights. It is as you said the hue will be balanced. Also experimented with the frosted glass if it would affect the hue.

  

  

  School 05.png

  1333 x 1000 - 2M

  

  

  School 06.png

  1333 x 1000 - 2M
• mjc1016 Posts: 15,001

  April 2016

  Ruri said:

   It doesnt come with a ceiling so I just threw a 45 degree plane with 6500k lights.

  Umm....that is a bigger reason why the light was doing what it was than the image used.  
• Tobor Posts: 2,300

  April 2016

  The easiest method for your scene is to render with Draw Dome off, and then you get a transparent background outside the window. Bring the image into Photoshop, GIMP, or most any other graphics program, and slug your image of choice under the scene. 

  Another method is to create a primitive plane, and place it outside the window. Apply the Iray Uber shader to it, and then select the image you want to use in the Base Color node. Set Glossy Weight and Glossy Reflectivity to 0. Rotate the plane so that it's properly oriented. The plane won't be UV mapped, so you may need to adjust the tiling to get the image to better scale onto the plane. If the image is too bright, choose a gray tone for the Base Color (or you may colorize it by changing the hue).

  If you do this a lot, there are cyclorama planes available that are UV mapped and more easily accept an image. Some are morphed with a curve, and/or allow you to control the morph. Of couse, you can create your own curve morph with one or more deformers..

  You only need to use a dome, or dome segment, if you can see a considerable portion of the sky or background. Otherwise, these tried-and-true techniques will solve your problem with the least amount of time and fuss.
• timetwist Posts: 52

  March 2017

  One additional option would be to adjust Render Settings -> Environment -> Environment Intensity.  This setting governs the amount of light produced by the environment map.  Moving this dial towards zero will reduce the overall lighting effect on the scene.  If this is the only lighting in the scene, it would be necessary to add additional lights.