Rendering Tutorials > Reducing Complexity in Your Renderings > Particle Trees >
Creating Billboard Tree Maps

In this lesson, you will choose a tree from the 3ds Max Design library of ready-made plant objects and edit its material to resemble an elm in spring. You will save this object as a .tif image, ready to be projected onto the billboards of your particle system.

NoteIn addition to the tree objects available in 3ds Max Design, there are a number of commercially available plug-ins, such as Forest from Itoo Software, or RPC from ArchVision, that offer a wide range of alternative tree species.

Create a tree:

1. On the main toolbar, click (Render Setup).
2. In the Render Setup dialog Common panel Common Parameters rollout Output Size group, set Width and Height to 512.

   Each particle, or billboard, you generate from the particle system will be perfectly square, so the resolution of the map you want to use for the tree must be square as well.

   A value of 1024 x 1024 or even higher is permissible, but the higher the resolution, the longer it will take to render the particle trees.

3. Close the Render Setup dialog.
4. On the Create panel, click (Geometry). Open the Objects drop-down list, and choose AEC Extended.
5. On the Object Type rollout, click Foliage and on the Favorite Plants rollout click American Elm.
6. Click anywhere in the Perspective viewport to place the tree.
7. Right-click to exit object creation mode.

Position the tree so it will render as a well-behaved billboard:

1. Activate the Front viewport and press P to switch to a Perspective view.
2. Click (Zoom Extents).
3. Click the Point-of-View (POV) viewport label and choose Show Safe Frames. Change the viewport shading mode to Smooth + Highlights (you can press F3).

   The safe frame displays as a yellow square, indicating the extent of the rendering area.

   Perspective view with the safe frame displayed

4. Use (Pan) and (Zoom) to reposition the tree until it fully occupies the safe area.

   Tree repositioned to fill the safe area

   Now you need to make sure the base of the tree trunk is centered precisely at the bottom midpoint of the frame. In doing so, you ensure that the trunk of this tree will be aligned with the tree shadow that you’ll derive from this image.

5. Click the Perspective viewport’s General label (“[+]”) and choose Configure.
6. In the Viewport Configuration dialog Safe Frames panel Setup group, turn off User Safe Lock, then turn on User Safe.
7. Set the User Safe Horizontal spinner to 100.0, the Vertical spinner to 0.0, then click OK.

   A purple vertical guide line displays in the viewport safe area. (This guide line is actually a rectangular safe-frame area that has no width.)

   User safe area that acts as a guideline for centering the tree in the frame

8. Move the tree along its X axis until the center of the trunk base is aligned with the purple line.

   The next procedure shows how to replace the tree with another one that might be more to your liking.

Find a tree configuration that you like:

1. Go to the Modify panel. On the Parameters rollout, click the New button to the left of Seed until you see a tree you prefer.
2. If 3ds Max Design displaces the tree trunk, move the base of the tree along its X axis until it is aligned with the center line of the safe frame again.

   This time, also make sure the tree base extends slightly below the bottom edge of the safe area. This will cause the particle tree to slightly sink in to the emitter object and form a solid connection with the ground. Also, make sure no leaves or tree branches extend beyond the safe area.

   Base of the tree repositioned so it extends slightly into the safe area

Render the tree:

1. On the main menu, choose Rendering Gamma/LUT Setup.
2. 3ds Max Design opens the Preferences dialog to the Gamma And LUT tab. Turn on Enable Gamma/LUT correction. Make sure that Gamma is chosen, and that the gamma value is set to 2.2.

   Turn on both options in the Materials and Colors group as well: Affect Color Selectors and Affect Material Editor.

   Adding gamma correction improves the appearance of renderings.

3. On the main toolbar, click (Render Production).

   3ds Max Design renders the tree using the default render settings. The trunk color is not realistic, and the leaves are too uniform in color. To correct this problem, you will change their material diffuse values.

4. Minimize the Rendered Frame Window.

Change the material of the trunk:

1. Open the Slate Material Editor.
2. On the Slate Material Editor toolbar, click (Pick Material From Object), then in a viewport, click any part of the tree.

   3ds Max Design displays the BasicElm material in the Slate Material Editor active View.

3. In the Slate Material Editor, click (Zoom Extents).

   The material tree looks complicated because BasicElm is a Multi/Sub-Object material, but it really is not as complicated as it looks.

4. Double-click the main BasicElm material node, the node at the right of the tree, so you can see the material parameters in the Parameter Editor panel at the right of the Slate Material Editor.

   The Multi/Sub-Object Basic Parameters rollout shows how the BasicElm material contains five sub-materials, assigned separately to the trunk, branches, and leaves.

   NoteThe Canopy sub-material is the material shown in viewports when the tree object is not selected.

   Now you will change the Diffuse values of the Trunk sub-material to improve the appearance of the tree trunk.

5. In the active View, click to select the first sub-material at the top of the View, which is the node for the Trunk sub-material.
6. Click (Zoom Extents Selected), and then pan out in the View a bit so you can see the Trunk material node and the map and controller already assigned to it. When you’re done, right-click an empty area of the View to return to selection mode.
7. In the Material/Map Browser panel at the left, locate the Noise map (it is in the Maps Standard group), drag this entry into the active View, and then wire it to the Trunk sub-materials Diffuse Color socket.
8. Double-click the Noise map node so you can see its parameters.
9. On the Noise Parameters rollout, choose Fractal for the noise type, and set the Size spinner to 5.0.
10. Click the Color #1 color swatch and choose a medium-dark brown color, (such as R=77, G=41, B=5), then click the Color #2 color swatch and choose a light tan or beige color (such as R=146, G=124, B=102).

Render the tree to see the result:

1. Minimize the Slate Material Editor.
2. Render the Perspective viewport to see the new diffuse values you set for the Trunk sub-material. If you are not satisfied with the result, feel free to make further changes to the material color.

   With lighter, noise-mapped colors, the trunk looks more convincing and also more elm-like.

   Next, you will copy the diffuse values of the trunk to the branches.

Use the new Trunk submaterial for the branches:

1. Restore the Slate Material Editor window.
2. In the active View, Pan downward in the View so you can see the Branch0 and Branch1 nodes. When you have finished panning, right-click an empty area of the View to return to selection mode.
3. Click the Branch0 sub-material node, then press Delete.
4. Delete the Branch1 sub-material node as well.
5. Wire the Trunk sub-material node to the main BasicElm (2) and (3) sub-material sockets that used to contain the Branch0 and Branch1 sub-materials.
6. With your cursor in the active View, press L to rearrange the layout of the material tree.

   With only three sub-materials, the material tree is simpler than it was.

   Now all the branches match the trunk, as you can see if you render the Perspective viewport again.

Change the material of the leaves:

1. Double-click the Leaves sub-material node (now the second sub-material from the top) so you can see its parameters.
2. Drag another Noise map from the Browser into the active View, and wire the Noise map node to the Diffuse Color socket of the Leaves sub-material.
   TipAfter you add and wire the new Noise node, press L again to clean up the layout of the active View.
3. Double-click the new Noise map node so you can see its parameters.
4. On the Noise Parameters rollout, choose Fractal for the noise type, and set the Size spinner to 3.0.
5. Also on the Noise Parameters rollout, set the Noise Threshold High value to 0.7 and the Low value to 0.3.

   These values will increase the level of sharpness between the two colors you are about to choose.

6. Click the Color #1 color swatch and choose a medium-dark green color, (such as R=0, G=73, B=0), then click the Color #2 color swatch and choose a light green color (such as R= 175, G=189, B=171).
7. Minimize the Slate Material Editor.
8. Render the tree to see the new diffuse values for the leaf material.

   Notice how the two-color combination makes for more realistic leaves.

Check the alpha channel:

1. On the Rendered Frame Window, click (Display Alpha Channel) to view the alpha channel of the tree object in the rendering.

   Alpha channel of the tree object rendering

   The alpha information provides the shape of the cutout for the particle trees you will generate later.

   Now you now need to save the tree to an image file format that includes alpha information.

2. Turn off (Display Alpha Channel).

Save the “billboard” image of the tree in spring foliage:

1. On the Rendered Frame Window, click (Save Image).
2. In the Save Image dialog File Name field, type my_elm_spring.tif, then click Save.

   3ds Max Design opens the TIF Image Control dialog. In the Image Type group, make sure that 8-Bit Color is chosen, and Store Alpha Channel is on.

   NoteYou can save your file in a format other than .tif, but be sure to choose a format that stores alpha information. Formats such as .png and .tga can include alpha, whereas .jpg and .bmp cannot.

   The particle system you create in the next lesson can use this tree image to populate a forest. To introduce some variation to the scene, you will create a second tree image to be referenced by the particle system as well.

Create fall foliage for the tree, and save that image:

1. In the Perspective viewport, select the tree object and on the Modify panel Parameters rollout, click the New button to the left of Seed.
2. Continue clicking the button until you obtain a tree you like.
3. Set the Density spinner to 0.75 and press Enter.

   This value reduces the number of leaves on the tree.

4. If you need to, move the tree trunk along its X axis again so it is properly centered on the vertical midpoint of the safe area.
5. Restore the Slate Material Editor window.
6. On the Noise Parameters rollout, change Color #1 and Color #2 for the Leaves sub-material to red and orange respectively.
7. Render the Perspective viewport.

   Tree object with fall-like parameters

   By reducing the number of leaves and adjusting the leaf colors, you have created a tree that is suited to a fall scene.

8. On the Rendered Frame Window, click Save Image, then on the Save Image dialog File Name field, type my_elm_fall.tif and click Save. Be sure to specify the 8-bit and alpha channel options.

   At this point, you could create as many different sizes, leaf density, pruning level, colors, and species of trees as you like to be referenced by the particle system. In this tutorial, however, you already have a dozen tree types made for you, sufficient to create a convincing-looking forest.

Save the scene:

- For future reference and adjustments, save the scene as my_elmtree.max.

Next

Creating a Particle System