Lighting an interior scene by firelight - constructive criticism and advice needed!

[DigitalDirt]

Hi everyone, this is my first post and I’m hoping for a little constructive criticism/ suggestions/ advice rather than help with a specific problem!

I’m an archaeologist and specialise in digital reconstruction, I work mostly in 3ds max with Vray (though only recently made the leap from Mental Ray so I’m still learning!). At the moment I’m working on reconstructing a house from the prehistoric settlement of Skara Brae in Orkney and I’m trying to work out the best way to go about lighting the scene. I suppose it’s tricky because my situation is a little different from a conventional CG artist because of the archaeological research element. I’m limited by the evidence we have for the site so I can’t use the same degree of ‘artistic licence’ as most people working with 3ds max can as I have set lighting sources.

For example the central hearths in the houses at Skara Brae would have been burning animal dung (lovely, I know), dried seaweed and some twigs as wood was a scarce resource in Orkney in prehistory. So as much as a roaring fire would help to light the scene better, I have to stick with a low light smouldering fire for historical accuracy. To try and push the boundaries of my artistic licence I’ve modelled an opening in the roof (my archaeological reasoning is to allow smoke to escape from the house – my artistic licence reasoning is to mix in a little natural light to brighten things up a bit!).

The lighting for the scene is as follows: I’m using HDRI lighting for the natural light with a Vray dome light outside the house and a Vray sky portal plane over the hole in the roof. Inside I have two Vray spherical lights with a bit of a warm colour in the fireplace, these will also be animated with a bit of noise to get a fire flicker, and I have a slightly glowing material on the fire embers. I had a Vray sun in the scene also but the light it was casting onto the wall was a bit bright and distracting for the atmosphere and tension I was trying to create and it wasn’t adding much ambient light to the scene so I’ve turned it off. I’ve looked at a lot of campfire photos for reference and I know a firelight effect seems to give an orange glow with cold blue shadows where the firelight doesn’t reach. The render I’ve attached is quite speckled with artefacts in the light, like around the stone axe and the fireplace, though I expect tweaking the render settings will sort this.

I’m using a Vray physical camera and have played about with the settings to lighten things up a bit, but I don’t want to over-expose it. I’m planning on adding a bit of fog to give the scene a smoky effect and maybe experiment with volumetric light at least for the stills from this project, though for render times when I animate it I’ll have to watch that it doesn’t take hours a frame!

What I’m hoping you guys can help me out with is a little advice on what I could tweak in the scene to improve it. Mostly in terms of lighting but also in general – I know the seated character isn’t the best; I’m working on my character modelling! Once I get the lighting right I’ll add in more details, some more dirt and scattered twigs on the floor, maybe some additional harvested plants and artefacts lying around etc. I think adding more mess and detail will add to the realism of the scene?

Anyway, any constructive criticism and advice to up the realism and atmosphere in terms of both lighting and scene content would be greatly appreciated!

What would you guys do?
Alice

[Morbid Angel]

I think you have the right idea in mind about the lighting. As you said you have to keep the fire low, would help to actually see the fire in the frame to be able to judge how low it is. What I would do is try to push the sky lighting from the top a bit more to give nice rim, and also try to accentuate the rims from the fire, then you can also render those lighting passes and add a bit of glow in comp that's a pretty basic thing one would try.

[DigitalDirt]

A few reference photos and a render...

Just realised it might be a bit more helpful to add a few images of the house I'm trying to reconstruct so you can see what I'm dealing with and maybe get more of a sense of the space! Obviously the ruins of the site are in daylight and electric lighting today as you can see from the attached photos, though in the past (as my reconstruction is trying to achieve) it would have been very dark, being roofed and lit only by a central hearth.

So the images attached are,

1. A general view inside House 7 at Skara Brae with yours truly in the shot for scale!



2. A dodgy fisheye shot to give you an idea of the entire space, where the bright light is is about where the cg camera is in my scene.



3. A view looking into House 7 from outside.



4. A different view in my cg scene looking through the entrance into the house (like photo 3) which will eventually be part of a camera path animation moving into the interior from the passageway outside....might be best to view this one with the lights off/curtains closed as it's very dark! I'll have a play with the ISO and shutter speed settings on the Vray physical camera!



Any advice for improvements would be greatly appreciated

[DigitalDirt]

Hi Dmitry, thanks for your reply I'll do as you suggest and push the lighting a bit more and hopefully that will give more of a contrast between the fire and the natural light. I had a max fire gizmo in the scene in an earlier render but it looked really obviously fake (and fume FX although beautiful is expensive so that's not an option for me!) so I took it out again and was just planning on going with smouldering embers rather than any visible flame, but I think you're right, it looks odd without visible fire...

If I had time (and I may well do if this project goes further than just being my research project and they want images/animations at the visitor centre onsite) then I'd look into enlisting one of my animator friends to camera track stock footage fire from a campfire or something similar into the animation, though for the minute I'll keep it simple!

Thanks again, really appreciate your advice and I'll post more renders as this comes together

[Sawyer]

Alice - you have my dream job. I got into doing 3d while I was in Crete imaging what Minos would look like reconstructed.

Anyway - my thoughts on lighting are to use lighting like a paint brush to convey the mood of the scene - dont get caught up in the technical aspects of lightning a scene. So much of what we see our brain interprets and the technical rendering of light will often fall flat compared to the story you want to tell. Lighten up the scene so it reads better. Some more light and we can see more whats going on.

[DigitalDirt]

Hi Sawyer,

Haha thank you! It is a lot of fun, though I still have lots to learn in terms of cg - that's what makes it an exciting method for archaeological research though, always a new challenge with each site

I see what you mean about using lighting to convey the mood of the scene and to tell a story, I think up until this point I've perhaps been restricting myself by keeping the lighting sources "realistic" so to speak (that'll be the archaeologist in me shouting louder than my artistic side!), in the fire and the natural light from the opening in the roof - Maybe if I use a bit more artistic licence to, for example, add a warm directional light in front of the character to cast a dramatic shadow on the wall behind that could up the drama?

If I consider the story I want to tell with this reconstruction I'd say I want the viewer to feel apprehensive of the seated character, I'll have a play with some more lights and see what I come up with!

Thanks for your advice, really helpful!

Alice

[Sawyer]

Coming from architecture we have this confusion about lighting. Most architects say they want to see their designs in "real world conditions" which usually means they want to see what the space with the lighting as they designed it. But then they review architectural photography books as a sample of what they have in mind or show it as an example as what they want the illustration to show. But in reality no photographer will shoot a site as is. Usually you do a preshoot to figure out the lighting conditions take polaroids, sample different lights at different times of day, add fill lights etc. Its a big deal to light space so it appears how we think it appears to our mind.

[DigitalDirt]

Work in progress...

Ok, Sawyer I took your advice and thought of how I could use lighting more "like a paintbrush" and combined it with Dmitrys' advice of ramping up the back lighting/rim lights and this was the result...



I added a couple of back lights (shadows off) with a slightly blue/grey colour behind the seated character to bring her out from the background a bit more and to create that red fire/blue shadows effect I talked about in my earlier post. I also switched the HDRI light coming in through the opening in the roof to a more dusky image to try and get the effect of moonlight coming in. I'm going to try and push it a little more, though I want the scene to keep a bit of the softness it has now and not look too much like an HDR picture with the contrasting colours pushed too far. And I managed to create a bit of a shadow behind the character on the back wall which makes her look a bit more intimidating and dramatic!

In terms of the fire, I've tried to create the effect of embers, it's still a bit of a work in progress and today I actually managed to find a dirt cheap student licence for Phoenix FD 2.0...so Skara Brae may have proper fire after all!

It's almost there and I'm much happier with the result after your advice guys so thank you! Any further constructive criticism to improve the photorealism let me know, I think I may try to light her face a bit more as it looks a little overly orange at the moment and of course I will be filling the house with a bit of smoke soon too - going for archaeological accuracy of course!

Thanks again!

[glorybound]

here is quick Google on, "Fire in a Cave". I think you did great, but maybe boost the intensity of your glow.

https://www.google.com/search?q=fire+in+a+cave&hl=en&rlz=1C1CHFX_enUS492U S492&prmd=imvns&source=lnms&tbm=isch&sa=X&ei=3BNBU O6ZBYPSqQHFsIHgCQ&sqi=2&ved=0CAgQ_AUoAQ&biw=1280&b ih=939

[Sawyer]

Looking good. I did like the blue highlights the first image had - I think the blue with the red sell the night shots.

[YoyoBoy]

Linear workflow would help this tremendously, if you aren't already working that way. There are many threads here about it you can search.

[DigitalDirt]

Thanks guys!

Bobby, I had a look through some of the Google images and I think something like this is what I'm going for in terms of glow around the fire...well in my case around the embers until my dongle with Phoenix FD arrives! -



I didn't want to up the intensity of the lights in the fire as I'm pretty happy with the way the scene is lit at the moment, so I tried to add a glow effect around the embers using a gizmo and the Vray Environment fog effect. I really like the effect but it's really expensive in terms of render times - pushed the render from about 40 mins to well over an hour, then spent about 45 mins trying to render the last two little bits, so as you can see I cancelled the render early! Can you suggest another way I could go about this and achieve a glow effect around the fire pit?



I was planning on using the fog to create a hanging smoke effect in the rafters as well, but if it's adding this much time to the render it's going to be a nightmare to process the animation, even with access to a render farm at uni!

Sawyer, I've ramped up the rim lights a little to get a bit more blue in the scene, I'll have a play around with the hdri dome light that was casting the light blue highlights before and see what happens!

Thanks again

[DigitalDirt]

Hi Geoff,

Ah-ha! I had thought I was using linear workflow with the gamma settings I had, but after a quick Google search and read through of a few threads I've realised I may not have been using it properly (only just switched to using Vray about a fortnight ago so hopefully that excuses me for being a bit slow here!). I'll have a go at changing the settings suggested in these posts -

http://www.davidfleet.com/tutorials/linear-workflow

http://www.workshop.mintviz.com/tuto...y-and-3ds-max/

and let you know how I get on!

Many thanks

Alice

[yyk]

Now that is an interesting project!

If it were me, I would further ramp up the firelight to get more pronounced shadows dancing on the walls and play with the light source so that I'd get nice, long and sharp shadows cast from the girl and all the small objects that are near the fireplace. Also the more intense fire would bring a few almost burnt out highlights on the ground nearest to the fire, which would bring some more depth along with the more contrasted shadows (especially on the right side where the large stone slabs cast shadows on the wall, darker shadows would look nice IMO!). You specifically mentioned you can't use a roaring fire here, but even the smallest firelight source would look bright and sharp once your eyes are used to the dark, not to mention with a camera you could use a longer exposure :P

If you are not doing a walkthrough animation that would restrict you to use a global lighting setup, have you considered ditching the HDR and just using a vray plane (or a sphere the size of the opening!) light with a deep blue color (more saturated than the one you are using now)? The roof opening is so small I doubt you'll actually benefit from using a HDRI, and you'd have more control playing with the directional parameter of a vray plane light.

Just my two cents. Good luck, I wish I could work on stuff like this for a change!

[DigitalDirt]

Hi Ville,

Thanks

Ok, so I've done as you suggested and switched to a Vray plane light over the roof opening (in the light-lister image attached it's called SkyPortal, that was me re-naming it, it's not actually a "Sky Portal" light, just a plane) and I've intensified the vray lights in the fire though the shadows weren't much darker so I lowered the GI multiplier as you can see in the screen grabs from the render settings to try and get a better contrast - just experimenting really! I played around with the camera settings too, as after I got to grips with the linear workflow it looked a little washed out.

I figure it may help if I post some of my settings as I think maybe I'm still missing something, so here are some screen grabs below...





I'm not 100% sure I have my light cache settings done right, I followed the advice of another thread for interior night lighting and those were the settings suggested, though for some reason I get a Vray warning telling me I have "invalid light cache sample(s)". Though I'm getting closer to the results I want with a render time of only 35 minutes so it can't be a major issue!



Any glaring problems with my settings or lighting please let me know, almost there! I think getting some atmospheric effects (sparks and smoke) in will be next, and seeing what I can do with Phoenix FD when the dongle arrives! The fire looks a bit weird now that I've upped the intensity of the lights.

Thanks everyone for your advice honestly, I should have started using the forums a long time ago it's helped me out so much!

Alice