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Object Making Question

Discussion in 'Bob's Track Builder' started by stevem, May 18, 2013.

  1. stevem


    Does anyone know how to make Trees? I used a transparent png to make the model in sketchup 6 but it turned out like this.
  2. Jimlaad43

    Nice apex, I'll take it! Premium Member

    You've made the tree fine, you just need to make the black transparent.
    Go into the 'Edit materials' menu and find the object. Then click on the correct texture. Using the 'Set Transparent' (I think) bar, change it to 'Chroma' (or something). A box should appear next to it. Click on this and it should have a colour palette. Choose the colour you want to be transparent - seemingly black - and press OK. Apply it and check the model, the black should disappear. If it doesn't, change chroma to one of the others, but fiddle around with that section and it should work.
  3. stevem


    i figured it out but i changed the xpack material to chroma. thanks! it helps to read the xml files of the default xpack once in awhile.:)
  4. Don't use black as chroma color.. Chroma color = the exact RGB color that's not drawn. If you use black chroma with green trees you might end up with black borders around the opaque parts. Don't use Alpha transparency, there can be only one! (sorry, had to..) alpha transparency texture at any time overlapped in the viewport. (if you have two trees one in front, one in back, you see the transparent background behind the second tree projected in the forward tree.It looks weird and i'l bet i didn't explain it right..) It's also much more GPU consuming method, simple chroma key is 10 times faster (at least)

    What you do is take a color sample from the actual tree leaves, somewhere around where the transparency should start and use that as you chroma. You might get occasional pixel that's not suppose to be transparent but for trees, this is actually usefull. It might take a few tries to get it right. By the 4th tree texture you've made that way, you get it right every time at first try. By that time you should seriously start looking at how to make texture atlas, it'll be even better optimized for performance. And since trees are around the track by thousands, this is the place to implement the most strict optimizing methods. You can later change some individual trees to alpha transparency to get the best visual look, for ex close to TV cameras ;) But they are single features, you can spend a lot on those highlights (bridges, pits/grandstands, special objects like videoscreens etc) while keeping everything else simple you get the best looking track and keep good performance.
  5. stevem


    Looks like my problem was using Paint to resize them. Paint was changing the background. Using XnView now.