A subject I have been thinking about while keeping track of the ISI Track team and Tim W's tweets about track surveying. Many of us live close to kart or car racing tracks and I wonder what we can all do to survey these. Maybe for ISI (or related modders) or even ourselves to make. Maybe members of ISI can wade in on this topic with useful info for people that want to get involved What are the best pictures to take whilst on site? What kind of conditions is it best to take photographs in? How to approach circuit owners to get data? (What data is it useful to ask for?) Any other queries people have?
Generally speaking good texture reference shot is slighly darker (without extreme contrast) than "normal" photo. With HDR, bright white albedo (diffuse) map color is about 180,180,180 (RGB), which is good to keep in mind when shooting reference material. What is needed - material reference for grass, tarmac, gravel, verges, concrete, armcos, rumble stripes and other "general" surfaces. These photos should be "clean" overhead shots which you can make tileable textures. For example, pick place where tarmac is clean and contains minimum amount of details (stains, cracks etc.). This will reduce texture editing/building time in your dev pc, because then you don't have to edit out all those annoying small details which would look bad in tiled material. - track side objects needs two types of shots, material reference and isometric photos, which will help you model actual 3D shape of TSO. For example, when shooting building take pics perpendicular to the wall for material reference. Dont worry too much for lining you shooting angle perfectly, as perspective distortion is easy to fix in Photoshop. Of course you need some isometric pics as well for modelling reference. Don't bother to run around of all small tso's, as some general photo in good enough for barrels, trashcans and so on... - Vegetation, like treelines, invidual trees etc. needs clean perpendicular shots. Pick shooting place where there is no obstruction front of object and clean sky behind. This is important as editing out all "extra details" from vegetation textures reference material is very time consuming and annoying... - 360 degrees shots. When walking around the track shooting other ref material, take "all around" shots. Purpose of these shots is help you to place all tso's and give you impression surrounding terrain etc. Believe me, you do not remember position or shape of all these details when you are back in your dev pc and browse through hundreds of shots what you have taken... So how to shoot these 360 degrees shot? Stand middle of the track, shoot one shot straight ahead, rotate yourself 45 degrees left (keep your camera and hands still, camera will "follow" as you rotate your body) and take another shot, rotate yourself again 45 degrees and take another shot and so on... In the end you got 8 pics on that spot which you can stitch to panorama pic in Photoshop. Move on to the track and shoot another 360 degrees photos and so on... - Pic your reference shooting weather conditions carefully! Study weather forecast before travelling to the track. Best weather is cloudy, without straight sunlight. When building textures we need to edit out ALL lightning reflections, shadows etc. and balance texture to unform luminance. Straight sunlight gives absolutely too much contrast on photo, which makes it useless or increases editing time exponentially... Remember, rF2 gfx engine (with HDR) renders lightning per PIXEL base. If you have big contrast difference in your texture, it messes up lightning in game. This is actually something, which I encourage every track builder to test. Build very simple track scene (maybe 100 meters long straight with some tarmac, grass and piece of armco), edit textures and study end result in viewer. When you play around with this some time, you get yourself experience how gfx engine behaves and what kind of textures works best. This will help you ALOT when you are working on your actual track project. Another thing is wet weather... It's a big no-no for texture shooting. All reflections and color distortions is next to impossible to edit out from wet surfaces (this includes vegetation as well). If you get unlucky and track is wet, concentrate on 360 degrees shots and shoot texture reference when track is dry. - if possible, shoot onboard HD video around the track. If you cannot use car, bicycle is good alternative. If video shooting is not possible, take series of "straight ahead" photos between 40 - 60 meters distance from each other (with karting tracks, about half of that distance). When you preview these shot afterwards in correct order, you have kinda "onboard video" from still photos. - last but not least... Take lots of memorycards for your camera with you and fill them all! You can't have too much reference material. Don't forget to take enough batteries as well. You WILL NOT have time to recharge batteries middle of the shooting day. If you run out of batteries, you ruin your opportunity... Cheers!
I'll try a short version limited to refmats and generic pictures: Camera/Lens and shots position: You need a good DSLR (a good reflex camera with at least 10Mpx) and a normal lens (comparable to a 40/50mm for a 24x36 - 35mm). Short zooms are also good (but never go for a TELE) but be sure to use the proper focal lenght (around the same normal position) to grab refmat pictures. Avoid aggressive wide lens due the barrel distortion and too long zooms because they're (most of the time) very slow (around f/5.6 and above).Try to keep your camera in "orthogonal" position for your refmat picture; perpendicular for buildings and vertical surfaces and 90° for terrain details, curbs, stripes etc. The rule I use is just point down 90° my camera until I start seeing my foots in the viewfinder. Of course this depends on the focal length of your lens and that's also why you need a normal lens (or similar) to avoid too much distortion/vignetting/tricky AF etc... and a good amount of pixel/meter detail ratio. Furthermore with a fixed normal lens you're sure your terrain pictures will have the same pixel/meter ratio resolution (of course you have to use the same body position per picture). You can also grab very short distance shots for special details with great resolutions. Go Auto; don't bother with manual settings per shot or you'll end with a handful of good pictures and the 80% of stuff missing. You don't have the time to go manual so just go full Auto with NO flash (!) and you'll fix/calibrate everything in house. NEVER use the flash for refmats. Focus: If you are sure your camera has a good multi point A/F then go for it, but if your camera has a slow A/F and/or a cheap multi point system (I'd say most of the time for consumer DSLRs) just use the center point. Frame: When you need to grab a sequence of pictures to create (for example) a long piece of curb or a large area of grass, just try to move along a linear path (crab steps along the same curb path) and be sure to keep around 10% of the previous shot to make a good photo stitch. For square and large grass areas do the same, but just following this pattern: View attachment 15296 PANOS: As Jka said, panorama/360° are also important, especially for reality checks. Just find a good "spot" area (usually in the middle of the track) and do your 360° sequence. If you have a car I'd suggest to use a cheap tripod and move this shot session at the end of the track day, driving along the track and making a 360° for each corner entry/exit and straights. I'm saying that because the range of time you have for good refmats shots is SHORT (few hours before noon and few hours after), so could be better to not waste this part of time for 360° (which are most of the time just check/reference shots). Measures: When you are on track spend a bit of time to measure important stuff like armcos module sizes, curbs (especially the Z for rumble strips and 3D curbs), stripe sections etc. It is also good to make the first terrain shot of each main sequence with the measuring tape visible in the shot (with a foot of tape or 30cm visible) to give you the average pixel/meter ratio. Easy peasy; measure armcos before that photo shoot, measure curbs before that photo shoot etc etc.. Perspective: Without starting an infinite topic about picture triangulation, the perspective is very important to help you in modeling buildings and structures... so just try to not make too "artistic" angles around structures. Be linear and coherent as much as possible. More angles you have around a structure, better is. I'd say to keep at least 2 levels of shots for structures and buildings; distant shots for shape recognition and short distance for details and refmats. Color Reference: Try to make at least 5/10 shots (in a limited amount of time to skip the sun movement) of the track with a proper white balance (just use a white cardboard to do the WB balance). This way you'll have few more information about "real" colors so you can tune up your refmats color schemes. And last but not least...have fun!
