Architectural Interiors - Sizes, proportions and Units setup problem

[LightRays]

Hi everyone,

Posting here for the first time. I'm refining my skills at creating interior walkthroughs but have a problem regarding how big or small things appear. Vague explanation I know. Let me clarify. I created a simple 4 room setup from a CAD file and the central room measures 24 ft in width, 12ft in height (same for all rooms of course) and I placed a 6ft character in it with a table too. I set the camera to 10mm focal length and a render resolution of 1280x720. I can't set the camera to 35mm or something because then I just get zoomed in walls and a very tight view. But even now; everything seems so small! the 24ft wide room seems like 8ft wide. I set the units to US standard > Fractional Feet. I made the walls from the DWG cad file and even created a box 24ft wide to see if it fits the room which it did meaning the sized are precise. Please see the attached images. One image shows the scene and how it looks and the other shows the units setup. Everything seems abnormally small or undersized. How should I set it up? I have to be precise about the measurements as I will be using photometric lights in mental ray. Please help. Thanks

[ATTACH=CONFIG]45557[/ATTACH][ATTACH=CONFIG]45556[/ATTACH]

Edited November 2, 2011 by LightRays

[notamondayfan]

If all the measurements are correct, then that will be how the room will appear. To me the room doesn't look too small, 24ft isn't massive.

 

Find a real room of similar size, take a real camera, and see what you can see. The human eye is nothing like a camera, so when using standard cameras, there is always going to be a compromise.

 

There are some tricks you can try though, you could scale down your people, props, furniture, but I find this just tends to make images look false and would avoid this.

You could put the camera behind the wall, and use camera clipping, or delete the wall, so you can see more of the room. And I would generally populate the scene with small, well chosen props and furniture.

[Scott Schroeder]

It's your camera lens. 10mm in Max is an insanely wide angle and will really throw off sizes. Max can't seem to handle a camera lens at anything lower than 20mm and still mimic a real world camera lens.

 

However, a 24' room isn't all that big either and with a roof at 12', it will throw off your scale. If you had a standard 8' ceiling, it'd look different. But since the ceiling is so high, it all looks strange.

 

This is a real life 35mm-10mm camera shot. http://www.knoxcountyohio.com/Blog/Digital-Camera-Wide-Angle-Lens-Comparison

 

Look at how small the refrigerator looks in the 10mm compared to even the 17mm shot. Ultra wide angle lenses will throw your perspectives off.

Edited November 4, 2011 by VelvetElvis

[LightRays]

Hey,

Thanks for posting guys. Didn't check because I thought no one would reply Anyway, I think I'll try that scaling option and you're right...10mm is insane but I just did that so I could get more into the perspective. However, there are pincushion distortions coming up that way. Also looked at the refrigerator examples you posted. I really wish I could simulate a real 35mm camera in 3ds max. Man I got a lot of practice to do Oh and the 12' ceiling is a bit odd too but I kept it that high because I wanted to put a ceiling fan there hehe.

[Jim Mann]

All sizes look absolutely fine to me.

 

Be careful when discussing lens sizes in 3D programs though because the focal length in millimetres is relative and fairly meaningless when you don't know the film gate size. A good example would be DSLR cameras. Full format cameras like a Nikon D700 and a Canon 5D are full frame i.e. the sensor size correspnds to old 35mm film size. Most DSLR cameras use smaller sensors approx 24mm wide e.g. Nikon D300 or Canon 7D. The effect of this is that a smaller sensor gives a more powerful zoom i.e. a 100mm lens on the camera with the smaller sensor will give the equivalent of a 160mm lens on a full frame camera. By extension you need smaller lenses to achieve wider viewing angles on a smaller DSLR e.g. a 35mm lens on a smaller sensor is only the equivalent of a 50mm lens on a full frame camera.

 

If you need to check your view set up, begin with a 50mm lens using a 35mm gate/sensor. Thats roughly quivalent to the human eye with approx 40 degrees field of view. Yes, human vision is far greater than 40 degree field of view but its the distortion and representation relative to the distance from subject that you are trying to judge.

 

Hope I haven't confused you. Your scene proportions looks fine.

 

Jim

[LightRays]

Thanks Jim. I didn't know all that I just had a basic idea about equivalent focal lengths in digital cameras.

[410]

First of all my apologies for digging up an older thread.

 

I come from a motion picture film/tv background and I was noticing similar problems in 3ds Max.

 

To me, the focal lengths in Max seemed very tight so I did some quick research:

 

According to Nikon's website their 28mm focal length lenses have a 74° picture angle when used with a full frame sensor or 35mm SLR.

 

Jumping back to Max for a moment I checked the FOV on my camera with a 28mm lens and as I suspected, it was much tighter, coming in at 39.5°.

 

Here Jim makes a crucial point, field-of-view is affected by the sensor size or size of the film gate- a smaller sensor will produce a tighter FOV with the same focal length lens.

 

Okay, so what's my sensor size in Max? Well actually that depends on my render settings. In my haste to get decent size images for viewing on a computer or hdtv I'd changed my output size to 1920x1080 using the HDTV (video) preset (under Rendering/Render Setup/Common Tab/Common Parameters/Output Size).

 

This preset locks my sensor width or "Aperture Width" at 20.2mm which is far smaller than a standard 35mm film or full frame digital camera's sensor.

 

To fix this I created a new set of Custom presets using the full frame Aperture Width of 36mm, which is the standard not only for traditional film stills but for the newer digital stills and motion picture cameras.*

 

Now my 28mm focal length lens looks about right in 3ds Max. But according to its settings it's FOV was only 65.5°.

 

Seems I'd made another schoolboy error here you see, as Nikon measure their picture angle diagonally while 3ds Max defaults to measuring FOV horizontally. Simply switching the axis under the FOV drop-down selection to diagonal corrects this number to 75.4°.

 

Which isn't, I must notice, 74°; but it is close enough for me to put it down to rounding errors or inaccuracies in the Nikon website, and close enough that to all greater extents and purposes my lenses in 3ds Max behave as I'd expect them to behave with the cameras I'm using in the real world.

 

Apologies if that's been overly technical, I've tried to be specific and use the correct names for things. And thanks to everyone who's posted in this thread so far, you've helped me figure out where I was going wrong and find a working solution.

 

 

*Edit: This isn't quite accurate for video and motion picture. Explained below.

Edited January 9, 2012 by 410

[RyderSK]

Wow !! Actually that was incredibly informative ! And helpful

[LightRays]

I appreciate your input on this 410. It surely did explain a lot of things to me. And RyderSK, your portfolio is awesome man!

[410]

I just edited my post because I spotted another obvious error I've made that might cause some issues.

 

I've said that 36mm is the 'standard' film gate or digital sensor's aperture width. This is accurate for stills, but it isn't true for motion picture film or 'full frame' HD video.

 

While both stills film cameras and motion picture film cameras use exactly the same size 35mm film, there is a difference in the size of the gate or "Aperture Width". This is because movie cameras run the film down vertically past the gate, where stills cameras run it horizontally.

 

Effectively this means that 'full frame' for film movie cameras (and many of the new digital cine-cameras) is always smaller than 'full frame' for stills cameras.

 

The correct "Aperture Width" for full frame movie cameras is: ...well a little bit complicated to explain (and to the best of my knowledge it depends somewhat on the camera's internal movement), but generally speaking the current modern standard is 24.89mm (0.980").

 

So, for example, if you're matching an animated 3D scene to film/video footage; that's a really good starting point to make sure your lenses FOV match.

 

But of course I'd recommend if you're doing this for a professional production and the level of precision really matters, to find out exactly what format it was shot on and exactly what size gate or aperture width was used.

 

Again apologies if that's overly technical, and I'm sure most of us on here won't need this information, but hopefully it's helpful for those who do. Thanks again to everyone who's posted so far.

Edited January 9, 2012 by 410