How to create a dynamic scene: creating interactive terrains with moving objects and flows Jean-Marc Gauthier - Spring 2006 All Rights Reserved

Transcription

1 How to create a dynamic scene: creating interactive terrains with moving objects and flows Jean-Marc Gauthier - Spring 2006 All Rights Reserved This introduction to creating a dynamic scene includes several tutorials covering gravity, driving, cloning and pseudo-physics and real time physics. Part 1 shows how to use gravity in order to integrate simple models of plants or trees inside a landscape. Part 2 covers 3D objects or animated characters roaming around. For examples: driving on a terrain or driving an interactive tornado. Part 3 covers cloning objects inside a landscape. For example: cloning random trees on the ground Part 4 is about real time physics showing objects bouncing on the ground. For example: cubes falling on a forest of trees. Jean-Marc Gauthier All Rights Reserved Spring 2006 Part 1- Creating a floor, an interactive terrain using a displacement texture This tutorial covers ways to create terrains and how to use gravity in order to integrate simple models of plants or trees inside a landscape. Textured dunes: download at Introduction We use a file with a plane and a displacement behavior that has been already setup so you can edit it with virtually any kind of texture in order to create a terrain. Please note that this is very usefull if you want to update a terrain with new content on the fly or for animated terrains using canned video or realtime video as a displacement texture. The landscape is created With Dune color, for texture and with Dune black-and-white, for displacement map.

2 Please note that the pictures can be created in Photoshop or from a digital camera. You can use the same image for a texture and for a displacement map. You may end up using a black and white image for the displacement map because sometimes you want to have more control over the topography. A live video image can also be used to displace the mesh in real-time. + = Texture image Displacement Map image Textured terrain with displacement map

3 Textured river bed downloaded at The landscape is created with Riverboat color - texture and Riverboat black and white - displacement map created in Photoshop. Please note that in this case the pictures need to match very precisely in Photoshop, same size, same scale, and same position of graphics. Press play to activate riverdisplace.cmo, please note the effect of the displacement map on the terrain. Method 1- Reusing an existing terrain that you can download from This may look strange but you can create your own original terrain by editing this plane with your own color texture and displacement texture. Software like Bryce, Mojo World or Vue d Esprit are commercial products based on that technique. Edit a ready made file with plane and displacement texture Let s open the file called terrain displace.cmo

4 Method 2- Do it yourself. Creating a plane in Maya Step 1- In Maya, go to Create > Polygonal Plane with 40 by 40 subdivisions. Step 2 - Apply a shader and a texture to the plane. Go to Windows > Hypershade. Go to Create Maya Nodes, double click on Lambert shader. Step 1, select the Lambert shader icon. Step 2, go to the attributes window., click on the checker icon, the button to the right of :color Step 3, Goto the Create Render Node window, select 2D textures, check Normal > File. Load the texture in the Attribute window. Add an ambient light. Step 3 - Export the plane to Virtools as a 3D object. Make sure to UNCHECK Character in the Export Window. In Virtools, You can find a ready-made plane in the data resource folder on the 3D server > sciviz > Resources folder. In Virtools, go to Resources > Open Dataresource, select ClassResources.rsc. this loads the data resource folder. Go to 3D Entities > plane.nmo LMB + drag plane.mno in 3D Layout Step 4 - Go to Level Manager Set IC for the plane and set IC for the plane s mesh

5 Step 2 - Go to Building Blocks > Mesh Modifications >Local Deformations > Texture Displace, LMB+Drag the behavior on the plane. The following steps are the same for all the above methods:

6 Let s change the displacement map in order to create a new topography. Go to Level Manager > 3D Objects > Select the terrain called XFloor, doubleclick on the script called TextureDisplace. The behavior opens in the Schematic window. Double click on the Texture Displace BB, select a new texture for example riverboat-bw. Press Ok. Hit Play in the lower right corner of Virtools interface and test the new terrain. You can adjust the intensity of the displacement by changing the Red Scale or Alpha Scale parameters.

7 Let s change the texture visible on the surface of the terrain. Go to Level Manager > 3D Objects > Select the terrain called XFloor, right click on the name, choose Setup. The Setup window opens > Got to ObjectMeshes > Double click onvisibleplanepatch_mesh. In the PatchMesh window, go to VisiblePlaneMaterial. In the Material Setup Window, go to Texture and select a new texture for example riverboat-color. Press the Set IC button on the left side. Hit play, the new textures will be applied on the surface of the terrain. Save your file as terraindisplace.cmo

8 Two terrains: Terrain with displacement map and terrain with water displacement Part 2- Driving a 3D object on a terrain using pseudo-physics A- Setting up a cube or a sphere on the terrain You can import a sphere or cube from Maya or use 3D objects from the class resources Add a sphere to the scene by using the data resource folder found in 3D server > sciviz > Resources folder. In Virtools, go to Resources > Open Dataresource, select ClassResources.rsc. this loads the data resource folder. Go to 3D Entities > SphereLowRes.nmo Step 1, Move the cube and the sphere above the terrain, select IC to confirm the new position. Please note that the 3D objects need to have their IC above the terrain in order to fall on the floor when Playback is activated. Step 2, we add Floor attribute to the terrain.

9 Go to Levels > Globals > 3DEntities > Floor, RMB on the name floor, select Setup in the pull down menu > go to the Floor Setup window > select Attribute > add Attributes > Floor Manager, Floor > Add Selected. The plane is added to a list of floor objects. Step 3, we create a cube with the keep on floor attribute. Objects can now fall on the floor or characters can walk on the floor.

10 Object Keep on Floor Behaviors added to cube and sphere Go to Building Blocks > 3D Transformations > Constraints > Object Keep on Floor V2, drag and drop the BB on the cube and on the sphere. Cube and sphere are located above the terrain. The terrain has a floor attribute and a Texture Displacement building block. Hit Playback the cube and the sphere fall on the floor. Troubleshooting: if the 3D objects fall through the terrain check is the floor has the floor attribute. B- Let s add a tornado to the cube. This shows how to drive a simple system with more than one object. You can skip this part if you prefer to work with the cube. In this case the tornado is made of a 3D frame with a particle emitter that you can drive on the terrain using the keyboard keys. Open the file pointparticlesystem.cmo found at Playing this file shows a vertical flow of particles which are small texture called Burst.jpg

11 Top, 2D particles = Burst.jpg. Bottom, 3D particles = sphere.mno Open the file sphereparticlesystem.cmo found at How to change a 2D particle emitter into a 3D particle emitter. Add a sphere to the scene by using the data resource folder found in 3D server > sciviz > Resources folder. In Virtools, go to Resources > Open Dataresource, select ClassResources.rsc. this loads the data resource folder. Go to 3D Entities > SphereLowRes.nmo Go to Level Manager > Levels > Globals > 3D Entities > select SphereLowRes Select the Group tool, go to Levels. Globals > Groups > rename the group SphereGroup Go to Shematic > Emitter > RMB on the pointparticle System building block > select Edit Settings > Particle Rendering, Object and Objects > SphereGroup

12 This shows a particle emitter emitting spheres This shows a particle emitter emitting sprites

13 You can tweak various parameters of the emitter including color and size changes while you play the emitter, press Apply in order to monitor the changes in real-time. Test and save your file as sphereparticlesystem.cmo Let s add the particle emitter on the surface of the terrain. We are going to merge riverdisplace.cmo with sphereparticlesystem.cmo Go to File > Load Composition, select riverdisplace.cmo Go to File > Merge Composition, select sphereparticlesystem.cmo A dialogue window pops up, and asks you about the status of 3D objects having the same names in both files, right click on the word ignore and choose rename Zoom in the terrain to find the small particle emitter

14 Save as riverdisplacesphere.cmo Open the file riverdisplacesphere.cmo found at Let s add the keep on floor behavior. 4 steps: Step 1, we add a Floor attribute to the terrain. Step 2, we create a cube with the keep on floor attribute. Step 3, we attach the Flow Emitter to the cube by creating a child-parent relationship. Step 4, we move the cube on the terrain by add driving controls to the cube.

15 First step, we add a Floor attribute to the terrain. Step 2, we create a cube with the keep on the floor attribute. I suggest using this blue cube to take care of the floor detection for the Emitter particle system. The emitter does not handle very well floor detection and emission at the same time on some terrains. The cube is added to the scene by using the data resource folder found in 3D server > sciviz > ClassResources. In Virtools, to load the data resource folder, go to Resources > Open Dataresource, select ClassResources.rsc. go to 3D Entities > cube.nmo Save as riverdisplace+sphereparticle+cube.cmo

16 Step 3, we attach the Flow Emitter to the cube by creating a child-parent relationship between the parent the blue cube and the child the emitter. The 3D Transformations > Basic > Add Child BB is added to the Cube Test the scene and save as riverdisplace+sphereparticle+cube+floor.cmo C- Let s drive the cube on the terrain Go to BB > Controls > Keyboard > Switch on Key, add the BB to the cube s scripts. Notice that the Switch on Key comes with two outputs and we need two more outputs. Right click on the Switch on Key and select Construct > Add Behavior Output in order to create two more outputs.

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18 Go To BB > 3D Transformations > Basic > Translate and rotate, add the BB to the cube s scripts. Please take note how the BB are linked together.

19 Settings for the Driving behavior.

20 Let s create a stationary camera in order to follow the particle system in motion. Step 1 dolly your perspective view for the desired position and create a camera called New Camera. Step 2, go to Level Manager > Camera, select New Camera. Step 3, Go to BB drag and drop BB > Camera > Montage > Set as active Camera, on New Camera. Step 4, right click on New Camera, choose Setup. In Target Camera Setup, go to Target, select Emitter, Set IC. Test the Driving Behavior and save as riverdisplace+sphereparticle+cubedriving+floor.cmo found at Let s encapsulate the Driving behavior so you can reuse it in another project.

21 From top to bottom Step 1, Right click on the gray field of the script, choose Draw Behavior Graph Step 2, Draw the enclosure for the new BB Step 3, re-link the new BB with the Cube s connector, Right click on the text Graph 2, choose Rename.

22 From top to bottom Step 4, Rename the BB Driving Step 2, Double click to collapse the new BB Step 3, Right click on the BB, choose Save As, save as a MyData ResourceFolder >Behavior Graph Part 3- Cloning fixed objects on a terrain. For example trees Download the file at Step 1 - If the tree is a 3D Entity, apply the Object Keep on floor BB to 3D Entity > Drag on 3D Entity Tree Step 1- If the Tree is a Character, for example an animated tree Go to Building Blocks > Characters > Constraints > Enhanced Character Keep on Floor apply to Character > Drag on character Tree Step 2 - Group trees in tree Group

23 Please note that the illustration shows a sphere group. Go to Level Manager > Levels > Globals > 3D Entities > select Tree. Select the Group tool, go to Levels. Globals > Groups > rename the group Tree Group Use the same steps for a Tree Character. Step 2 Go to Resources > Open Dataresource, select ClassResources.rsc. this loads the data resource folder. Go to Behavior Graphs > Kinematics > Cloning Fixed Objects. Drag the BB in Level Manager > Levels > Globals > Groups > Tree Group In Schematic, double click on the BB to edit the parameters > Counter = number of cloned trees. Please note that this BB is cloning random trees. Trees cloning BB Part 4 - Real Physics Objects bouncing on a terrain Download the file at Step 1 Apply Real Physics to the Floor

24 Go To Building Blocks > Physics > Creation > Physicalize, check Fixed, check Enable Collision, Convex = enter the mesh name, Surface Name = enter the surface name for the floor which derives from the mesh name_surface. Step 2 - If the tree is a 3D Entity, apply the Object Keep on floor BB to 3D Entity > Drag on 3D Entity Tree Step 2- If the Tree is a Character, for example an animated tree Go to Building Blocks > Characters > Constraints > Enhanced Character Keep on Floor apply to Character > Drag on character Tree Group trees in Tree Group Please note that the illustration shows a sphere group. Go to Level Manager > Levels > Globals > 3D Entities > select Tree. Select the Group tool, go to Levels > Globals > Groups > New Group, rename the group Tree Group Use the same steps for a Tree Character.

25 Step 3 Cloning FIXED objects with Physics = Trees Go to Resources > Open Dataresource, select ClassResources.rsc. this loads the data resource folder. Go to Behavior Graphs > Kinematics > Cloning Moving Objects with Physics. Drag the BB in Level Manager > Levels > Globals > Groups > Tree Group Step 4 Cloning MOVING objects with Physics = Cubes or Spheres Go to Resources > Open Dataresource, select ClassResources.rsc. this loads the data resource folder. Go to Behavior Graphs > Kinematics > Cloning Moving Objects with Physics. Drag the BB in Level Manager > Levels > Globals > Groups > Cube Group In Schematic, double click on the BB to edit the parameters > Counter = number of cloned trees. Please note that this BB is cloning random trees. Physicalize >

26 Trees and spheres interact with the terrain and with each other. Adding and cloning moving objects

27 Adding and cloning fixed objects