I think the lighting works, just roughen it up a bit. Put a rougher bump map onto the surface, also maybe add some grain and fog effects to the CG layer.

If you have the film and the CG layers done in a suitable format for After Effects/Premiere, I could have a go at compositing it in the next week or two.

The new KB Videos coming soon.

Pretty sure you've got the lighting wrong on the letters. It's hard to tell with the shot as it is but there's a highlight on Maxime's right leg that suggests the light should be coming in right to left, whereas the letters look lit left to right. That's one of the reasons it looks less convincing.

Lack of shadows/reflection under the letters is another. You can fake that in 3D software by making a dummy bit of wall, doing separate shadow/reflection passes and comping them into your shot.

I'd offer to help but I don't have the time or the skills to do it justice, unfortunately.

Thanks for the input so far!

Honesty, it's already unreasonably dirty and scratchy and bump-map-y. Way more than most real LEGO. So I don't think pumping that up even higher is going to help. The only exception being I didn't get around to adding that noisey bump texture to the sloped edges yet. And there's no fog on Maxime so there's shouldn't be on the CGI, either. I do plan to add some very subtle grain and lens aberration on the letters (as well as grain on the whole shot), haven't done that yet but it wouldn't be particularly obvious at 720p anyway.

Not especially. I don't necessarily want to crank it up high enough to achieve that. I was going for a (subtle) miniaturization effect.

I should clarify, my idea is that this would be a somewhat surreal effect that will obviously be a composite of some kind. I don't want to make huge LEGO letters that actually match in scale. I'm more concerned with them looking like they're rendered and lit realistically.

I wish I could do bevels. Carrara doesn't have a good way of adding those. I probably just need higher quality piece models to resolve that issue.

I agree with most of these points, hadn't noticed the light on his leg.

Nope. The tilt-shift was added in post to both the letters and the footage. The shot was shot in deep focus. So the blur matches because it was all added simultaneously.

I can't really help, but I can nitpick: It could be just me, but the letters don't seem exactly aligned with the wall. It looks as though they start further away from the edge than they end, when I compare the first M and the E.

I could try working with that, yeah! Carrara supports dozens of formats. I'd say most of the standard ones but not .blend or .max. .LWO, .3ds, and .obj would all be fine I believe.

Do you have an automated way of replacing LDR bricks? Because that's been a hangup for me. I can remodel bricks to look nicer but then I'm trying to shift them into the proper coordinates, one-by-one, which takes hours with moderately complex models like these. Carrara also handles each piece as a unique master model, so I can't, for instance, automatically add slope texture to all of even one kind of slope piece at once.

Nathan wants to revise the letter models (I made this quickly for mockup purposes and the A has floating pieces right now), once we have a revised version of it I could send you what I've got.

Thank you for the offer to make a video tutorial, but I feel like I can't take the time to learn Blender right now for this single purpose, simply because I don't have enough time (too many things to get done on this doc by a somewhat challenging deadline).

If somebody could get me high quality parts versions of a series of LDraw models, all fairly basic lettering like this one, that I could import into Carrara, though, I'd be very grateful! And you'd get film credit. I'm not sure what Chris Salt had in mind, it may be a similar method of replacing parts with higher quality ones.

Thank you. After discussing with MindGame I think we might take a stab at compositing real LEGO models into the shots. I should know pretty soon if that's going to work, if it doesn't I'll contact you!

Carrara controls: Ctrl+D to duplicate objects, essentially inheriting texture and any changes to master mesh applies to all.  Enable Snap to Grid via View>Grid so your pieces can move 1 inch at a time, for example.

I've kept many of my CG brick pieces in separate .blend files (one for slopes, one for bricks, plates, etc.).  Let me know if you want them or give me a list of pieces I can put together for you.

They've all been modified based on Littlebrick's inset approach.  This makes the edges rounded (if you set smooth creases) and gives the illusion of gaps between pieces without having to bevel or scale down objects.  See pics.

Best format option for Blender to Carrara is .FBX.  When you import, slide Crease Angle to 90 to set all crease to smooth.