Scattering mr Proxies in a Scene
 
 
 

Now that you have your tree proxies properly defined, you need a way to instance them multiple times and distribute them across your terrain. You will complete this task using the Scatter utility.

Load the Scatter utility:

  1. Open a web browser and type www.maxplugins.de.
  2. From the MAX Plugins web page list, choose the version of 3ds Max you are currently using.
  3. From the main menu, next to Plugin search, type scatter and click Search.
  4. Click Scatter v1.63 on the Name/Download column and click Save.

    A zip browser opens.

  5. Choose the scatter.dlu file that applies to your computer setup, either 32- or 64-bit.

  6. Extract the scatter.dlu file and save it to your 3ds Max program folder > plugins directory.
  7. Use the Explorer to look at your \plugins folder. If the scatter.dlu file is in a folder called \max2009_32 or \max2009_64, move it to the main \plugins folder.
  8. Close 3ds Max, then restart. Open your scene from the previous lesson, or open the file 8_trees.max.

Define the instance and scatter operations:

  1. Go to the Utilities panel and on the Utilities rollout, click More.

  2. On the Utilities dialog, choose Scatter from the list and click OK.

    The Scatter rollout > Distribution Method group is set to the parameters you initially need.

    One hundred objects will be distributed across the terrain, aligned vertically on their Z axis. In the Copy Method group, Scatter is the name assigned to the copy method. The method itself is Instance, the best distribution technique since it requires less memory and saves a good deal of render time.

  3. On the Offset Method group > Translate Offset Z spinners, type -0.2 and -0.5 to sink the trees slightly into the Plane01 object. This way, if the trees are situated on a steep hill in the terrain, no part of their tree base will appear above ground.
  4. On the Rotate Offset Z spinners, type -180 and 180 to give the trees a random rotation on their Z axis so they are not all oriented vertically in the same way.
  5. On the Scale Offset X spinners, type 50 and 120 to give the trees a random differential in size, with a value of 100 being 100% of the default size of the proxy.
  6. Turn on Uniform Scale From X.

    Next, you will choose which proxy objects to include in the scatter operation.

  7. In the Scattered Objects + Weight group, click the top button initially labeled “None”, and in any viewport, select a tree proxy.

    The name of the selected tree displays on the button, indicating that it is now associated with a weight control.

  8. Repeat the previous step for each of the seven remaining tree proxies.

    At their default weight values of 1.0, each tree is equally represented in the scatter operation.

  9. In this lesson, you need to create a fall scene. Assign the Oak-Spring and Elm-Spring proxies a value of 0.2 to reduce their population to 20% of the other types. Assign the Elm-Summer and Oak-Summer proxies a value of 0.7.

  10. In the Emitter Object group, click the button initially labeled “None”, and in any viewport pick the Plane01 object.

    This identifies Plane01, the rolling terrain, as the object across which tree proxies will be scattered.

    Before you launch the scatter operation, you will create a layer. This way, if you do not like how the proxies are distributed in the scene, you can delete them as a group and start over.

  11. On the main toolbar, right-click on any gray area and choose Layers.

  12. Make sure nothing is selected in the viewports and on the Layers toolbar, click Create New Layer.
  13. On the Create New Layer dialog > Name box, type ProxyTrees and click OK.

    Now, any tree proxies you create in the scatter operation will be placed on this layer.

  14. On the Scatter rollout, below the Emitter Object group, click Apply.

    The scatter utility starts to populate your emitter object, Plane01, with 100 tree proxies according to the rotational and size variation as well as the mix of tree types you defined in the preceding steps.

    Trees in the river bed after random scatter operation

  15. Maximize the Top viewport and zoom in to the riverbed.

    Because the trees were scattered at random, some of the proxies ended up in the river. To solve this problem, you will scatter the tree proxies using a different method.

Use polygon selection to define the instance and scatter operations:

  1. On the Layers toolbar, click Select Objects In Current Layer and press Delete.

    This removes all the scattered trees from the scene.

  2. Select the Plane01 object and in the Modify panel > Modifier List, choose Edit Poly.

  3. On the Selection rollout, click Polygon Selection.

  4. On the main toolbar, click Select Object and zoom out until the entire Plane01object is visible.
  5. Press Ctrl+A to select all the polygons in Plane01.

    Plane01 with all polygons selected

  6. On the main toolbar, click Paint Selection Region.
  7. Hold down the Alt key and paint over the river until all the polygons are deselected.

    Plane01 with polygons in riverbed deselected

  8. Continue holding down the Alt key, and paint to deselect the region where the camera is located, then paint over more areas on the terrain to create clearings in the forest.

    Open spaces created from deselected polygons

  9. On the Selection rollout, click Polygon Selection again to exit selection mode.
  10. Go to the Utilities Panel and in the Scatter Rollout > Distribution Group, turn on Use Selected Faces.

  11. Scroll down and click Apply to re-distribute the tree proxies.

    No trees appear in areas where you deselected the polygons, including the riverbed and the small clearing where the camera is positioned.

  12. Switch back to four-viewport view, right-click the Camera01 viewport to activate it, and on the main toolbar, click Render Production.

    Rendered scene, showing open spaces created by deselected polygons

    If you are not satisfied with the tree placement, you can start over by selecting the layer, deleting the trees and using polygon selection to re-define the scatter area.

    You can also, at any time, add tree proxies individually to your scene.

  13. On the Utility panel > Scatter rollout, scroll down and click Paint.
  14. Make sure the terrain object is selected, then click once for every tree you wish to add to the scene.
  15. Render the scene again to view the result.

    Rendered scene, after new trees were added to the terrain

    If you like, compare your work with a finished version of this scene, proxy-trees_final.max.

Summary

When rendering in mental ray, mr Proxies are a useful way to create a large scene with many instances of a similar object.

While mr Proxy objects cannot be edited directly, they offer the advantage of freeing up memory and speeding render time.