How to render a dusk or dawn exterior

[tuts3d]

Hi Guys

Just wanted to get some insights on basic light settings for this kind of renderings. For me it has always been a bit harder to setup exterior renders than interior in octane. Any advise would greatly be appreciated.

[glimpse]

I'd say stepping for a good hdr map + adding some warm interior lights would be the easier setup. Kernel depends on mats and other small things, but overall PMC or PT should work out of the box =) strat a WIP and post some pictures, I'm sure Guys will give You some advice based on Your project. For now it's hard to say something more without geometry and environment =)

[tuts3d]

Thanks Glimpes for the reply. Though, I cannot post the actual project due to nds agreement with the client. Here's a sample of what they like the render to look. I think there's quite some PP involved but any suggestions would be greatly appreciated.

[sdwhitton]

with something like this - it's heavily photoshopped

so, to give a fighting chance what I'd say would be:

a. keep all glass separate i.e. render it in a different pass

b. maybe try a render of the model without glass with a neutral hdri image (your ambient pass)

c. a second render of the model without glass with a sun environment, with the ambient colour set to black in the sun environment, if you're using 1.2, just to get the 'sun effect' only

maybe option c isn't truly necessary, but it does give you the opportunity to ham it up later in photoshop

d. a zDepth pass, of a geometry group with both model and glass, just so you can play with the haze effect, which is obvious in that render posted

e. a render of the model with glass, black material, solid and totally reflective, (could just a sun environment for this, or a cloudy hdri, or render two versions, sunlight and cloudy hdri and merge them however you like)

f. a material id render so you can get the alpha channel for the glass

so, you'd have your ambient pass in photoshop, over the top of that your sun alone pass, set to screen or linear dodge / add, 80, 90, 100%

over that, your glass layer, set to whatever opacity you like (or the client wants....) , maybe two copies, one set at 'normal' 20%, one at screen 50% or whatever to make it look more glassy, highlights stronger etc

and then a layer filled with the medium colour of your chosen sky background, light blue, with a layer mask based on the zDepth... 10, 20, 30%, to give it that atmospheric hazy look)


would think all of these could be rendered with a direct lighting kernel, to keep things speedy..

if you need more 'sun' then duplicate the sun render, play with the opacities etc, can also play with the ambient layer, make it more blue, dark etc

With all of these 'lighting pass' renders you could add a photo filter adjustment layer (make sure to group it with the layer so it doesn't affect the others), to again ham it up, make the sun more golden, the ambient cooler, etc

hope all of the above helps... this technique above works really well with matching a render to a background photo

[tuts3d]

Hi Sdwhitton

Thanks for the advised! Will try as you suggested.

[kavorka]

I find rendering out an alpha in my 3d app (Blender) leads to much better accuracy than rendering out a material ID pass for composting.

[sdwhitton]

yep, certainly a lot crisper, and there's none of 'select colour range' business, which is a faff!