Creating Billboard Tree Maps
 
 
 

In this lesson, you will choose a tree from the 3ds Max 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, 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.

Define a tree object:

  1. Open 3ds Max and on the main toolbar, click Render Setup.
  2. In the Render Setup dialog > Common panel > Common Parameters roll> 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. From the Create panel > Objects list, choose AEC Extended.

  4. On the Object Type rollout, click Foliage and on the Favorite Plants rollout click American Elm.

  5. Click anywhere in the Perspective viewport to place the tree.
  6. Right-click to exit object creation mode.
  7. Activate the Front viewport and press P to switch to Perspective view.
  8. Click the viewport Perspective label and choose Show Safe Frames. Make sure viewport shading mode is set to Smooth And Highlights.

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

    Perspective view with the safe frame displayed

  9. Use the Pan and Zoom controls to reposition the tree until it fully occupies the safe area.

    Tree repositioned to fill the safe area

    You now need to make sure the base of the tree trunk is centered precisely at the bottom mid point of the frame. In doing so, you ensure that the trunk of this tree and the shadow of the second tree you’ll derive from this image, will be properly aligned.

  10. Click the Perspective viewport plus (+) sign and choose Configure.
  11. In the Viewport Configuration dialog > Safe Frames panel > Setup group, turn off User Safe Lock, then turn on User Safe.
  12. Set the User Safe Horizontal spinner to 100.0, the Vertical spinner to 0.0, and click OK.

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

    User safe area that acts as a guideline to center the tree in the frame

  13. Reposition the tree until the center of the trunk base is aligned with the purple line.

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

  14. On the Modify panel > Parameters rollout, click the New button to the left of Seed until you see a tree you prefer.

  15. Reposition the base of the tree as you did in step 13.

    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, be sure no leaves or tree branches extend beyond the safe area.

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

  16. On the main toolbar, click Render Production.

    Rendered version of the tree object

    The tree is rendered using the default 3dsMax render settings. The trunk is quite dark, and the leaves are too uniform in color. To correct this problem, you will change their material diffuse values.

Edit the Tree Materials

  1. Close the rendered frame and press M to open the Material Editor.

    The top left corner sample slot is already active. You will use this slot to edit the default tree material.

  2. Click the eye dropper icon and in any viewport click on any part of the tree to display the tree material parameters.

    The Multi/Sub-Object Basic Parameters rollout shows how the tree material has been created at a sub-object level, with sub-materials assigned separately to the trunk, branches, and leaves.

    NoteThe Canopy sub-material is for viewport display when the tree object is not selected.

    You will now change the diffuse values of the trunk material to brighten up the rendered image.

  3. On the Multi/Sub-Object Basic Parameters rollout, click Trunk (Standard).
  4. On the Blinn Basic Parameters rollout > Diffuse option, click the map button.

  5. On the Material/Map Browser dialog, double-click on Noise.

  6. On the Noise Parameters rollout, choose Fractal for noise type, and set the Size spinner to 5.0.

  7. Click the Color #1 color chip and choose a medium-dark brown color, (such as R: 77, G:41, B:5), then click the Color #2 color chip and choose a light tan or beige color (such as R: 146, G:124, B:102).

  8. Render the Perspective viewport to see the new diffuse values you set for the tree trunk material. If you are not satisfied with the result, feel free to make further changes to the material color.

    Tree object rendering after new diffuse values were added to the trunk

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

  9. Click Go To Parent twice to go up two levels and display the parameters of the parent material.
  10. Click and drag the Trunk material as an instance to the Branch0 material, then do the same for the Branch1 material.

  11. On the Multi/Sub-Object Basic Parameters rollout, click Leaves (Standard).
  12. On the Blinn Basic Parameters rollout > Diffuse option, click the map button and on the Material/Map Browser dialog, double-click on Noise.
  13. On the Noise parameters rollout, choose Fractal for noise type, and set the Size spinner to 3.0.
  14. Set the Noise Threshold High spinner to 0.7 and the Low spinner to 0.3.

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

  15. Click the Color #1 color chip and choose a medium-dark green color, (such as R: 0, G:73, B:0), then click the Color #2 color chip and choose a light green color (such as R: 175, G:189, B:171).

  16. Render the tree to see the new diffuse values for the leaf material.

    Tree rendering with new diffuse values added to the branches and leaves

    Note how the two-color combination makes for a more realistic result.

  17. On the rendered frame window, click the alpha button to view the alpha channel of the tree object in the render.

    The alpha information provides the shape of the cutout for the particle trees you will later generate. You now need to save the tree object in an image file format that includes alpha information.

    Alpha channel of the tree object rendering

  18. On the rendered frame, click Save Image, and on the Save Image dialog File Name field, type my_elm_spring.tif, then click Save.

    If you specified .tif as your file type, the TIF Image Control dialog opens. In the Image Type group, make sure 8-Bit Color is specified and Store Alpha Channel is on. If you chose another format, make sure to specify the alpha channel in your file setting.

    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 cannot.

    The particle system you are about to create can now 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 a second tree 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, reposition the tree trunk as you did earlier so it is properly situated within the safe area.
  5. On the Material Editor > Noise Parameters rollout, change Color #1 and Color #2 chips for the Leaves sub-material to red and orange respectively.
  6. Render the image.

    Tree object with fall-like parameters

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

  7. On the rendered frame, 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.

Next

Creating a Particle System