Omita
04-29-2003, 02:51 AM
[Updated: Image 8.28.2005, I re-added the original image from my post at a users request. And I also updated the post bellow.]
http://www.omita.com/Forums/Boards/tree_wip.jpg
Umm... I'm new to realtime tree's. So any advice would be great.
This first attempt is using Shells... 35 shells in this tree so the tree can have as few as 136 polys, however it doesn't have as nice of a shape.
-Omita
http://boards.omita.com/tree_wip.jpg
[Updated: 8/28/2005:]
Here is one of the later versions I created. I added a few more triangles just for detail. Depending on your resources this style is still very effective. Basically, the next level would be to make the basic tree and larger branches and use shells for the smaller branches.
So, bellow you can see the texture. This case was hand shot using a NikonD100, Manual Focus helps. But you want a nice really over cast day or a nice blue sky to easily mask your photo, and then do some Photoshop work to clean up the colors and usually clone some branches. I usually try to take a photo of a loan branch that is sticking out.
So here are the basic steps.
1. Cleaning up the texture and making a nice alpha channel
2. Actually put the transparency data on a "alpha channel" (I am not sure what CS2 does...but I often just use the TGA exporter from Photoshop 6 or 7. You'll see why.)
3. Copy your color layer and Gaussian Blur the image a couple times then I usually duplicate the blurred image an flatten them.
4. Then take the original clean texture and have it infront of the blurry version, but the blurry versions should extend the color data past the alpha.
5. Last of all, take the average color for the leaves and make that a background layer behind everything and your done.
So... if you are wondering why? Here's the answer. Things have changed a lot and this is very engine specific but... you are trying to make sure that your image doesn't MIP map poorly. If you don't have over lap when your texture is drawn at lower resolutions you will often get a white edge on your texture. The can look really nasty if the tree is far away. Obviously, is you are a wiz at painting you can do this process by hand, but time is money and it's just the end result that matter.
If you can animate the hulls and have proper sorting these tree’s can look really good, especially at a little distance.
Last of all... one of the biggest flaws about tree's like this are they can be sorting nightmares. Some engines are better then other when it comes to sorting. If you are sorting on a triangle level or even pixel level you are going to be in pretty good shape. If you have to hand sort or rely on per-object sorting then you might get some weird over lap.
Oh... I don't have a texture on the trunk... so adding a trunk texture can help a lot. And you can easily fake the shadow with a shadow texture (shadow maps)... :)
http://boards.omita.com/tree_wip2.jpg
http://www.omita.com/Forums/Boards/tree_wip.jpg
Umm... I'm new to realtime tree's. So any advice would be great.
This first attempt is using Shells... 35 shells in this tree so the tree can have as few as 136 polys, however it doesn't have as nice of a shape.
-Omita
http://boards.omita.com/tree_wip.jpg
[Updated: 8/28/2005:]
Here is one of the later versions I created. I added a few more triangles just for detail. Depending on your resources this style is still very effective. Basically, the next level would be to make the basic tree and larger branches and use shells for the smaller branches.
So, bellow you can see the texture. This case was hand shot using a NikonD100, Manual Focus helps. But you want a nice really over cast day or a nice blue sky to easily mask your photo, and then do some Photoshop work to clean up the colors and usually clone some branches. I usually try to take a photo of a loan branch that is sticking out.
So here are the basic steps.
1. Cleaning up the texture and making a nice alpha channel
2. Actually put the transparency data on a "alpha channel" (I am not sure what CS2 does...but I often just use the TGA exporter from Photoshop 6 or 7. You'll see why.)
3. Copy your color layer and Gaussian Blur the image a couple times then I usually duplicate the blurred image an flatten them.
4. Then take the original clean texture and have it infront of the blurry version, but the blurry versions should extend the color data past the alpha.
5. Last of all, take the average color for the leaves and make that a background layer behind everything and your done.
So... if you are wondering why? Here's the answer. Things have changed a lot and this is very engine specific but... you are trying to make sure that your image doesn't MIP map poorly. If you don't have over lap when your texture is drawn at lower resolutions you will often get a white edge on your texture. The can look really nasty if the tree is far away. Obviously, is you are a wiz at painting you can do this process by hand, but time is money and it's just the end result that matter.
If you can animate the hulls and have proper sorting these tree’s can look really good, especially at a little distance.
Last of all... one of the biggest flaws about tree's like this are they can be sorting nightmares. Some engines are better then other when it comes to sorting. If you are sorting on a triangle level or even pixel level you are going to be in pretty good shape. If you have to hand sort or rely on per-object sorting then you might get some weird over lap.
Oh... I don't have a texture on the trunk... so adding a trunk texture can help a lot. And you can easily fake the shadow with a shadow texture (shadow maps)... :)
http://boards.omita.com/tree_wip2.jpg