F o l i a g e

3D trees

Here are some suggestions based on my 3DO foliage workflow:

» Model trees at several ages. You can start with juvenile, adult, and mature versions and see if that gives you enough variety. I prefer 5 different models, but it depends on the size of your terrain and how much time you have to render (more models=lots more polygons). If you're using tree software, models should already be in the appropriate real-world units.
» Tree models are very polygon heavy. Reduce the polygons in a 3D app (I use LW). XfrogTUNE does this, but the version I have (1.0) doesn't do a very good job for VNS use.
» If you're going to mix 3DO trees with IO trees, use rendered versions of the 3D trees as images for best results.
» 3DO foliage is governed by the controls in the 3DO Editor. If you exported your 3D tree in the correct real-world meters it should import at the correct height in VNS. If your trees are not the correct height as 3DOs, you need to Scale them to the correct height in the 3DO Editor. If the 3DO tree has the correct height in the 3DO Editor, a corresponding height range in the Ecosystem or FE editor will render correctly.

Related tutorials:

Tree Modeling Software
Tree Images from 3D Models

3D trees: Pine needles not sharp

If the transparency mask is working and the needles don't seem clear, it may be due to image resolution limitations:

» Needles are extremely small image features, typically less than a pixel wide in a rendered image.  This can make for 'muddy' clumps of needles because there aren't enough pixels to resolve them.
» Many of the model leaves are viewed at an angle.  The greater the angle, the more the image looks smeared and the needle clump tightened visually.

You can test this by zooming in on leaves and rendering them.  Needle clarity will improve as you get closer.

Accurate shadows

Use Fractal Depth Maps, aka FDMs, aka Fractal Maps (Terrain Parameter Editor).

Crop rows and orchards

For crop rows, try an Ecosystem with a stripes density texture. Orchards are best planted explicitly with a Foliage Effect. You can digitize your placement vectors in VNS or use a vector tool to create a grid with the appropriate row and tree spacing.

Dense foliage flickers in animation (VNS 3)

This may be 'z fighting' and happens when the two Foliage Objects are nearly the same distance away. Reduce the foliage density (Ecosystems) or stem location (Foliage Effects).

Distance Dissolve, Absolute Pixels vs Relative to Image Height

Ecotype Editor Ecotype page. If a tree dissolves out to a color or texture when it's shorter than two pixels high (Absolute Pixels), it will dissolve out sooner in a smaller render (such as a preview) than in a larger render. If you want Dissolve Height to be independent of your output image resolution, select the Relative to Image Height radio button instead. This will apply to all Ecotypes using Distance Dissolve. This will likely increase the render time of your previews since WCS will be using a smaller Dissolve Height for smaller rendered images. The good news is that your preview and final renders will be comparable as far as Distance Dissolve is concerned.

Distance Dissolve with remote imagery: Tinting Ecosystem foliage for a better transition

If you're using remote imagery for a Distance Dissolve texture, the transition from foliage to texture may be overly obvious. Try tinting the foliage with the remote imagery. Go to the Image Object Library, add a Color Control attribute to each foliage image, and disable 'use color'. In the Ecosystem Ecotype apply the remote imagery to the Foliage Object 'Replace Gray' texture as a georeferenced planar image.

If the colors don't quite match (the foliage is likely to be darker than the aerial image), make a copy of the image and adjust its saturation and brightness as necessary. [Contributed by Adam Hauldren]

Foliage Effect growing in ATfx road

Foliage effects are an explicit placement. WCS and VNS assume that when you place one, you really mean place one. As far as I know, nothing overrides a FE. If you don't want FE trees in your ATfx road, don't plant them there.

Growing trees

WCS is not a plant growing program. It just renders what you give it. You usually use images for foliage and that's the easiest way to grow things, too.

Fast and easy method that doesn't really grow trees. Keyframe the height of the Foliage Object or Ecotype to go from 0 to the full growth height.
Sequence of images showing tree at progressive growth stages. This takes a lot more time and work because you have to create the animated image sequence of tree growth. You could paint them, progressively model a 3D tree and render to images, or use a program that does it for you. Add the resulting image sequence as a Sequence in the Image Object Library.
Compositing with LW or Max RPF/RLA sequence. Export the Scene+DEM to LW or Max, animate and render the 3D trees in LW/Max, and composite the sequence back in WCS.
Sequence of 3D Objects in VNS. Use a program designed to create a series of growth 3D trees (Xfrog, for example). Use VNS Scenarios to enable/disable objects as necessary.

Halos around rendered foliage

Open the offending image(s) in Photoshop and check the RGB colors where the halo appears. If the color is not exactly the same as the transparency color, then that's your problem. To fix it, repaint the halo areas with the transparency color. To prevent it in future foliage, always edit foliage photographs without anti-aliasing.

Mindy Bieging has and excellent Foliage Creation tutorial on foliage creation at 3DN World.

An easy way to check a non-JPG image for JPG compression is to increase the contrast in Photoshop and slide the brightness control through the range from very dark to very bright. When you see artifacts that are 8
pixels square, you are seeing the damage done by JPEG's DCT lossy compression. [Contributed by Chris Hanson]

Hedges

Try a Foliage Effect. Digitize the hedge vector in Connect mode with a spacing appropriate for bush spacing. Don't forget that you can use 3D Objects as Foliage Objects, so Xfrog or TreePro bushes (or anybody else's, for that matter) will be easy to use.

Image sources

3DN World Components: Images
ImageCELs
Marlin Studios
Xfrog

Planimetric and Overhead views

When I make planimetric or overhead views I use either 3D trees or images of 3D trees rendered from overhead
(example). When you use ground level views of foliage, VNS does the best it can given those images, which usually means squashing them vertically. It often misses or chops some of the foliage, which is what the 'Render from Overhead' option is for on the Render Options > Misc page.

3DN FAQ: http://3dnature.com/faq/index.php?qid=156&catid=15

References

Flora of North America
US Department of Agriculture Plants Database

Tinting Foliage and Ecosystems (VNS 3)

Instead of tediously applying a tint to each image in the Ecosystem, you can apply it as a masked Post Process after the render is done. This also lets you experiment easily, as a Post Process can be set to preview mode and it will continually re-apply its changes to an existing rendered preview as you tinker.

Create a Post Process with a Texture Overlay event. Set the texture to be a Planar image and create either a georeferenced or a basic tiling texture. Next, add an Intensity texture on the Texture Overlay event. Set the Element Type to include/exclude. In the bottom include/exclude list, choose Include, set the Class to Ecosystem, and add one of your Ecosystems to the list. Make sure you have a rendered preview, then check the Preview Only checkbox in the Post Process Editor. It should apply your change to the render. You can turn the Intensity value down to limit the amount of texture application it performs.

(From a support ticket by Chris Hanson 8/2008)

Trees get darker toward light source

Most obvious with a north-looking camera and an early morning or lake afternoon sun. Image Objects face the camera and have 3D Shading by default, so the trees toward the sun side of the view are backlit, making them darker. This mimics what happens in the real world, though it's more pronounced with the default 25% Back Light setting. Increase the Back Light % (try 50) and see how you like it. If you want a truly artificial and shadeless look, disable Apply 3D Shading.

This effect is easy to see if you look for it in the real world. Below is a south facing view photographed in early morning. The light source (sun) is off to the left. The trees at the far left of the image (east) are backlit and appear darker than their counterparts on the far right, which are frontlit. A 50mm lens was used on a 35mm camera, with a FOV of about 38º. This is a narrow FOV compared to the default WCS perspective camera. A wider angle lens would show this effect even more, since it would take in a greater view area. This scan is as true to the original transparency as I could make it. The original slide was exposed according to scene light values placed in film zones to reproduce important scene values as close to their perceived values and value relationships as possible.

Whether or not the average person perceives this change in lighting through their eyes is not important because that's not how they evaluate renders (unless they just happen to be at the real world location, step outside, and hold it up for comparison ;). They compare it to other images, i.e., photographs. And we know how much pictures of the same scene can vary.

Trees missing or truncated in overhead or planimetric view

See Planimetric and Overhead views above and the 3DN FAQ.

Trees 'pop out' of animation at frame edges

This is usually caused by overscan values that are too small. Overscan is the percentage of frame width or height that is used to calculate the rendered image, but not rendered. If overscan is too low, foliage polygons outside the frame with foliage extending into the frame will not be considered for rendering. The foliage top (or side) will not be rendered and will 'pop out' of the animation. If this is happening at the bottom of the frame, increase Bottom Overscan on the Render Options Editor Size & Range page. If it's happening along the sides of the frame, increase Side Overscan.