how can I lighten up a fire in Iray?

Comments

• nemesis10 Posts: 3,794

  October 2017

  Toobis said:

  doing a scene for Iray where I wanted to lighten up the fire in it. As it stands now the fire is too dim and not very bright so is there a way to lighten it up so it looks like proper light fire? example in pic is what I mean as the render of the fire is wayyyy too dimmed down.

  Hopefully, the fire prop already has iray surfaces... If not, select the flame in the scene, select the flame and logs in the Surfaces Tab, apply the Daz iray ubershader,  select just the flames, change Emission to red/orange, up the lumens to 5000, render, adjust...
• L'Adair Posts: 9,479

  October 2017

  Toobis said:

  doing a scene for Iray where I wanted to lighten up the fire in it. As it stands now the fire is too dim and not very bright so is there a way to lighten it up so it looks like proper light fire? example in pic is what I mean as the render of the fire is wayyyy too dimmed down.

  I prefer to use the diffuse image in the Emissive Color parameter, rather than @nemesis10's suggestion.

  • If the object uses 3Delight materials, select the object in the scene tab, select the object in the Surfaces->Editor tab, double-click on the Iray Uber Base icon in the Surfaces->Presets.
  • In the Surfaces->Editor, select the material zone for the fire
  • Note the name of the image in the Base Color parameter
  • Scroll down to the Emissive Color parameter and add the image to the parameter
  • Set the color of the Emissive Color to White
  • Set Emission Temperature (K) to 0 (zero)
  • Set Luminance (cd/m^2) to 20
  • Set Luminance Units to Kcd/m^2

  Do a test render, (or set the viewport to Nvidia Iray, if your computer can handle it.) Now adjust Luminance until the flames are just bright enough to see the details. If you need the flames to put out more light, use a ghost a light. You can make that as bright as necessary, slightly behind the flame, and keep the details of the flame.

  If you want a warmer color, adjust the value for Emission Temperature. (Zero is off. Lower numbers are warmer/redder, higher numbers are cooler/bluer.) I like the 2900 to 3500 range for fire. You can also set the same temperature on your ghost light. (If you don't own KA's Iray Ghost Light Kit 1, you can use this tutorial from KA to create your own.)

  Here's a render I did recently that uses the fire, (and a couple of oil lamps,) to light the room. I used the exact same steps as I detailed above. (The image is dark, so you may want to click on it to see the full-size image.)

  
• jestmart Posts: 4,449

  October 2017

  The problem is most fire props are just a single plane with an image and transparency map so they can only emit light in two directions. Scaling a sphere so it encapcilates the fire and then appling a ghostlight effect to it emits light in all directions.