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My dream X-Pack: low poly cars

Discussion in 'Bob's Track Builder' started by Emery, May 19, 2010.

  1. I sure wish we had an X-pack of low-poly, photo-textured cars. Sorted by decade. When I say low-poly, I'm thinking of typical trackside cars with <1,000 polygons, preferably <100. A step above the "box car" tutorials.

    Sad thing about undertaking such a project is that there are sooo many models to create!

    I could be persuaded to go on a photo-taking expedition if someone can quickly make the models.
  2. Come to think of it, another good X-Pack would consist of crowd material.
  3. Very interested in this. I've made a low poly ambulance for Longford, it uses two b/w Chrysler ambulance photos as reference/textures from a guy in NZ, with permission. The model, even as low poly as it is, isn't any sort of a perfect recreation, but the idea isn't to stop and look at it. I also have a friend who was looking into helping me out with some vintage style crowds and marshals. If this xpack gets going i'll see if they mind sharing them.

    Longford really needs a lot of 60's cars to fill the surrounding paddocks/car parks, but the poly toll could get high, fast. Maybe a front row of models, then a few rows of 'car wall'
  4. Dave Stephenson

    Dave Stephenson
    Technical Administrator Staff

  5. [​IMG]

    tyres look like they need some air though :)
  6. This is how I do it in Blender.

    I go here and get textures
    you are allowed to use these textures for anything.

    I will do this one for the sake of this.
    I will save the smallest size front side and back.

    I have not done it in this project but you will want to set the images up properly, put them on one texture and make it a power of 2.

    Then in blender I will set it up like this (right click on the border of the window to split the work area)

    Put the mouse cursor over the left window and press numpad_3. that will switch it to the side view.
    In the top right numpad_1. This will set it to he front view
    In the bottom right ctrl + numpad_1. this will set it to the back view.

    Mouse over the left 3d window > space bar > add > mesh > plane. (you can see the plane I added in that screen ^^)

    Use tab key to switch between edit mode and object mode. or alternatively use the menu on the bottom toolbar to change.

    Right click to select the vertices, then use left click on the arrows to move it to where you want it. You will want to do something like this.

    See how I have the top 2 vertices selected? shift + right click to select multiple vertices, then press e to extrude them. move them to the next main point on the car (the bottom of the windows) and extrude again to make the cabin, also do the same for the bottom.

    Ctrl + tab and switch to edge select.
    Right click and select the 2 lower edges.

    Then press W and select subdivide multi, set it o 4 and press ok.
    You will end up with this.

    Ctrl + tab and switch back to vertices select mode.
    Select and move the vertices into position around the wheel arches.
    Spend a moment lining things up as best as possible, if you need to merge vertices, select the 2 vertices > W > merge.
    Using the edge select, extrude the edge at the bottom of the wheel arch and align it around the wheel.

    Press A, one or 2 times till it selects all, then in one of the right windows, align it to one side of the car.

    Switch back to edge select and in the left window (side view) select the edges all the way around the perimeter.
    Then go to one of the right windows and press e and extrude the edges, drag them out until the reach the centre point of the grid.

    Doh!, I forgot something, Notice how the model is a lot smaller on the front back view compared to the side view? I dunno why it does that but what you have to do is resize the image to match.
    Once you have done that, switch to vertices select, press B and swipe select all the outside vertices and drag them back into place.

    Ok, back on track.
    Move and adjust the vertices to match the image.. remember, the image could be distorted (as is in these pics), so getting it precise will look funny. What I would do it just move them around and make it look like a car. Middle mouse to rotate the view. When you have the shape press A till it selects all, then W > set smooth.
    Do the best you can, then we will go and unwrap it. Just remember you only need to make half of the car, the other half will be made with a mirror modifier.

    Now to the unwrapping, (the fun part)
    Up the top where it says 'SR:2-Model, click that and select "scripting', then in the right window at the left of the toolbar press the little icon and select UV image editor. You should see it like this.

    Using the numpad keys move the car around to the view you want to unwrap first. Press ctrl + tab and switch to face select mode, select the faces you want to unwrap, then press U and select unwrap from view.
    With the left window active press alt + Z to turn on the textures in the 3d view. Move the vertices in the right window to line up ( you might want to do some lens correction on the image before you do this) To move these vertices in the uv editor you have to click and drag the mouse, then let it go and you can move them. (weird I know but, once you get used to it its easy) To resize it press S.

    Do this for all sides until it is all mapped out.

    Now, down the bottom in the buttons window, where it says modifiers, select mirror and select xy or z to mirror the side you want to mirror. You will most likely need z if you have done it right.
    It might be too wide so just fix it up so it looks right.

    There is one step further you can go which is to apply the mirror modifier, which will turn the mirrored part into a mesh. Then you can uv map the other side of the front and back image to make it look right by selecting the mirrored mesh and using M in the UV window to flip it.

    Then set the scale.To scale the object, go into object mode, right click to select it, then press S and move the mouse till it reaches it's desired size.
    If you pivot the model in the 3d window you will see the grid a bit differently than when looking at it flat dead on. Each square is 10m. So in the image below the square is 20m wide.

    With the car resized it is now just under 2m wide

    Then move the object up so that the bottom of the model sits on the xy axis lines.

    One last thing is to set a material. In the same part on the buttons window, go to the left and click 'new' in the materials section.

    And that's about it, all you have to do now is put it in object mode, right click to select, then export as 3ds > xpacker > BTB.

    This is just a simple way of doing it, I have not put too much detail into the model, its as rough as guts, I recommend you spend a bit more time making it look nicer. For the record, that model is 60 poly's.

    Here is the blend file (project file) You are free to use it in what ever you wish.

    [ED] dunno what's the go with he images. I tried to make them clickable thumbnails but the forums changed something and it didn't link the large image.
  7. Thanks, mianiak!

    I'm curious, with your well-practiced skills, how quickly did you make this model? I've tried some 3-D modeling and am jealous of folks that can do it quickly :trophy:

    "With the left window active press alt + Z to turn on the textures in the 3d view. Move the vertices in the right window to line up ( you might want to do some lens correction on the image before you do this)"
    By lens correction, do you mean squareing the image so the lens distortion is removed as much as possible? The sort of thing that would be done as prep before beginning the modeling, like powers of 2 for the image?
  8. That took me just over an hour, which included taking screenshots and posting them on pb as I went. It really only would take about 10-20 minutes to do it with no interruptions. It just takes practice, once you know how to use the tools you can go pretty fast.
    The most common tools I use are
    * Alt + tab, to change selection type.
    * A, to select all
    * B, to swipe select
    * Right click, to select
    * Shift + Right click, to select multiple
    * W, pop up menu for tools like subdivide merge etc.
    * E, Extrude

    By lens correction I mean prep work, in gimp or PS.
    It's best to use individual images for the guide images though, because if you use the texture you make, you will have troubles lining the background image up.
    What I would do is edit the single images and fix the lens distortion, then use them as the guide to make the model. Then use those images again but put them on one texture and map the uv's onto that.
    You can also select faces individually and unwrap them one by one, instead of all at once.

    There is one step further you can go which is to apply the mirror modifier, which will turn the mirrored part into a mesh. Then you can uv map the other side of the front and back image to make it look right by selecting the mirrored mesh and using M in the UV window to flip it. I will make a screenshot of that and add it to the guide.

    [ED] Ok I added that step in and I also added the scaling step in too.
  9. Experimenting with texture resolution on my 2560x1600 monitor, I find that 512x512 photo textures (complete uv wrap... left, right, front, back, top view squeezed into one picture) provides adequate detail for cars that are relatively close to the viewer (e.g. across a wide pit lane) and 256x256 works well for more distant cars (e.g. out in a parking lot). 128x128 could be used for cars in the back rows of parking lots, but the tracing & uv mapping is difficult because the highly pixelized image makes the body lines indistinct. Reserve 1024x1024 for the really large vehicles, such as big trucks and construction equipment.

    Do any of you have a different opinion?
  10. If you are using different sized textures for the same car it will not matter, because as you move away from them, the mip maps kick in to a lower resolution anyway, Extra textures would use up more processing than just the one with mips and 512 would be the absolute maximum you would want to go for a prop. I'd make it one standard size for an xpack That will keep it simple and be diverse at the same time.