HDR + SUN: possible?

[kwistenbiebel1]

Re: HDR + SUN: possible?

Hi Jackson,

Thanks for posting your findings.
However, in a real situation (architectural exterior), these settings don't seem to produce good results.
I applied the 'blend' to both the light as the background slot, but the HDR is not visible.
Instead I get a dark looking blue sky....

It seems not so intuitive to get a good Sky/HDR blend.

The tip Dalomar gave in another thread about using 0.3 sun intensity doesn't work properly either.
I guess he is referring to Rhino or Max when he stated that.

Why is it so difficult to get it right in Sketchup?....

[Jackson_cg]

Re: HDR + SUN: possible?

Kwist (I always wondered, do you prefer your real first name or your nickname?),

Sorry, I should have said that these settings apply only to lighting i.e. VfSU's environment slots. I've no idea if you can blend an HDR and sky as a background, but as the sky is just a gradient I imagine overlaying them would look pretty weird.

I know you know all this, but just in case anyone reading doesn't, the key benefit of being able to blend HDRI and sky is that it allows you much more adjustment of VfSU's lighting conditions while maintaining accurate SU shadows. The current VfSU sky setup is for "ideal" conditions, bluish sky, no clouds, etc. By combining it with HDRI you can tune it to be much whiter (or any colour of that matter) as is often the case especially with photomontages. By editing the HDRI you could reflect light (or absorb light) from adjacent buildings, water, etc.

The (unfinished!) image below uses the settings I posted above, but with a plain "Acolour" instead of HDRI in the B slot. The background is just a spherical sky rendered out from Vue 6i. All the vegetation is clipmapped pngs in the SU model so no post-processing.

Regards,
Jackson

[kwistenbiebel1]

Re: HDR + SUN: possible?

Cool result.
I must give it some more attention as it clearly can produce satidfying results.
Thanks for the tips.

...Nice looking clipmap trees here. Care to share which collection you're using?
(I know it is not nice to be asking these things )

[thomthom]

Re: HDR + SUN: possible?

hmm... had a quick look at VUE some time ago... never got around to use it to generate sky maps. Does it produce HDR skies?

[Jackson_cg]

Re: HDR + SUN: possible?

Thanks Kwist! All the clipmaps and components are homemade (partly on company time, so unfortunately I can't share any :-[), the smaller tree was a photo I took in the spring, I think the bigger tree was a Googled image from a gardening blog and the grass is a composite of 3 different grass images downloaded from Flickr (God, Flickr is a texturer's dream!). It took me 3 days to get the grass texture and spacing of the face-me grass clumps right so you don't see their bottom edges or repetition at eye level! The ferns are very simple 3D components with a png and clipmapped fern leaf applied to angled faces so they cast proper shadows unlike the trees and grass. Still not happy with the overall colours, everything's a bit too green, it need some more yellows and reds in the image. The funny thing is there are only 2 trees and 2 ground plants (1 is the grass) in the whole scene, but a bit of scale variation works wonders! I'm sure with a good HDRI (mine are all freebies and pretty crap) a blended environment could produce excellent results; as realistic as HDRI, but as accurate as SU's shadows.

Thom,

It's the only thing I use Vue for anymore (it was my primary renderer for years), but it is almost worth the money just for producing spherical skymaps. It's weather and lighting editor is AFAIK second-to-none, everything is adjustable: volumetric cloud type, density, cover, altitude, sky colour, fog, stars and all with instant preview so you know what you're getting as soon as you move a slider. Although Vue is slow at rendering models it'll render out a 4000x2000 spherical skymap in less than 20 minutes. Unfortunately, although it will save in HDRI format the damn files are LDR (like Evermotion's free "HDRIs" :)! Still, it's easy enough to make a copy in Photoshop, adjust the gamma or contrast, then adjust the exposure of each image and combine them in Photomatrix (or any other HDRI editor) to create your own HDRIs from Vue skymaps.

I'll look into the legality of sharing Vue created skymaps (they might be like Poser figures- under an iron-clad copyright), if it's OK I'll probably upload them somewhere as they're so useful.

Jackson