Ongoing questions. Please check back...

deathbycanon

1) I have an emissive primitive plane in my scene, I am going to need 3 of the exact same size and emissive settings, is there a way to duplicate? I tried ctrl c & ctrl v , couldn't be that lucky. :) 

2) when rendering canvases is there a way to isolate emissive light? Can I render it as a light group? I have tried using the emissive canvas but that didn't seem to do anything. Maybe I didn't check the boxes that needed checked??  I never know if anything works until my render is done so I thought I would ask in advance this time. :) 

3) I'm using an old 3delight set and the windows have textures that I don't want to loose (painted scene and panes) is there a way to let light through these without loosing the texture? 

4) I need a narrow soft light, narrow and directional like what you get when using a snoot, but I want really soft edges and shadows, like you get with a Larson  4x6 or natural light on a cloudy day. 

I'm tagging @algovincian and @TabascoJack because they are fabulously smart about these things and sometimes they are the only ones that seem to put up with my questions. 

v1si0n4ry

1) Select object you want to duplicate, go to Edit>Duplicate>Duplicate Node(s)

4) The bigger the emission area relative to the distance, the softer the shadows. Think about the sun. When the sky is clear, the sun seems like a tiny light source with a strong emission, creating very sharp shadows. When the sky is clouded and the sun covered, its emission is diffused across the clouds, creating a much more soft light. The same applies on iRay. Since iRay is a photorealistic engine, it's impossible to change the shadows a light will emit without changing the light emission properties or size itself. You could try and mess with the geometry and emission strength or use another non-emissive surface as a reflector to smooth out the light

algovincian

1. Edit -> Duplicate. I've changed my hotkeys, so I couldn't say what the default is. There are options (heirarchy and such), and you could also create instances depending on your needs: Create -> New Node Instance

2. There's something called LPE in Iray (Light Path Expressions). I personally only render out beauty canvases, but there is a lot more you can do. Here's a post from an Iray blog, as well as a relatively recent thread here to get you started:

http://blog.irayrender.com/post/76948894710/compositing-with-light-path-expressions

https://www.daz3d.com/forums/discussion/205886/light-path-expressions-iray

3. In Iray, the 2 settings that I've used to control "transparency" are the cutout opacity (which effects the opacity of the geometry directly) and refraction weight. You may find these links useful:

http://docs.daz3d.com/doku.php/public/software/dazstudio/4/referenceguide/interface/panes/surfaces/shaders/iray_uber_shader/shader_general_concepts/start

https://sickleyield.deviantart.com/journal/Iray-Surfaces-And-What-They-Mean-519346747

4. You can size an emissive plane any way you wish and use additional geometry to shape the light until you get the results you're after.

Hope this helps - be sure to post your results!

- Greg

 

 

deathbycanon

Thank you  @v1si0n4ry & @algovincian

I'm trying to light my character's face and a small area around them, and don't want a lot of spill onto the background. I'm going to go try a small circular emissive, it can't be too far away or to get the amount of light I want it would light the whole scene, so dimly lit and maybe bounce some light back in with a reflector to soften any shadows 

Then I'm going to go read those articles! 

 

TabascoJack

Sorry for the delay in responding - I haven't been on the forums in quite some time.

You can isolate emissives in canvases by using the Light Group Canvas.  This works for both photometric lights and emissive lights.   Assign the emissive to the group for that canvas, and that should do it.

I've got a section in my thread where I cover all the canvas types.

 

deathbycanon

TabascoJack said:

Sorry for the delay in responding - I haven't been on the forums in quite some time.

You can isolate emissives in canvases by using the Light Group Canvas.  This works for both photometric lights and emissive lights.   Assign the emissive to the group for that canvas, and that should do it.

I've got a section in my thread where I cover all the canvas types.

 

Thanks Jack!

maclean

If you want soft light, maybe the normal spotlight is a better bet. It has the option to change the geometry and size, and this is fairly close to real lights. If you use a small snoot light (a spot with disc geometry 5x5) + a larger spot (disc or rectangle 200x100), that should be a good start.

The good thing about Iray is that if you know anything about photography, the light options give you just about everything. At first, my natural insctinct was to use emissive planes, but I soon gave it up in favor of spotlights.