Asset Setup in CRYENGINE

Now we have our asset configured correctly, let's move on to the CRYENGINE side of preparing the asset to be used for production. Have an existing level open or create an empty level as the testing area for this asset.

Material

First, open the Material Editor and go to the tutorial_merged_mesh material under:

• <Your_Project>\Assets\Objects\tutorial\vegetation\02\grass\tutorial_merged_mesh\

If the export process is completed successfully for the material and geometry, you should have the material as shown. Note the correct folder structure and also the same SubId setup we configured inside the DCC tool. A lot of the fields have been filled out already through the export process (note the "Diffuse" texture path already filled in). But there are still a few options that we need to set ourselves

The rest is completed here in the CRYENGINE's Material Editor.

Pic1: Initial Material Editor overview

Material Settings

We only have to change two settings here the Shader and the Surface Type. We usually use the Vegetation shader and the surface type is also set to Vegetation. Select both from the drop down lists as shown in the Pic2.

Pic2: Material settings

Opacity Settings

Here we are using the default values that we setup in 3dsMax. Opacity at 100% and the AlphaTest set to 40.

Pic3: Opacity

Pic4: Re-cap of where this info came from in 3dsMax

Lighting

Under the Lighting Settings, we find the color parameters. To be correctly in line with the PBS pipeline, we have to:

• Set our Diffuse Color to pure white 255,255,255.
• Set the Specular Color within the 40 - 60 range (dark grey).
• Set the Smoothness slider to a low value such as 30.

Pic5: Lighting Settings

Texture Maps

The Texture Maps section should already have been filled out with our diffuse map.

Pic6: Texture map

Shader Generation Params

his tab in the Material Editor will show you different options depending on the shader type you assign to this material SubId. Since we have selected the vegetation shader, it has exposed the options that only apply to the vegetation. To continue, check the box for the Grass parameter. We want our asset to run through a cheaper and faster pipeline.

Pic7: Shader Generation Params

Shader Params

As you may have noticed, we jumped this section in favor of the Shader Generation Params first. We wanted to enable the Grass options first to expose all the parameters that we need to configure the asset correctly. Enabling the Grass parameter has exposed some additional parameters in the Shader Params section. It should now look like this (Pic8).

Pic8: Shader Params

Save the material

Inside the Material Editor, on the top tool bar, click the Save icon.

Pic9: Saving the material changes

Vegetation Editor

Before we continue to configure the material params, it will help if we place some of these grass objects down using the Vegetation Editor to get instant visual feedback as we update the material. We will not go into an in-depth tutorial of the Vegetation Editor here.

Create a vegetation category and add the grass

Under the Tools menu option, and select the Vegetation Editor.

Pic10: Selecting the Vegetation Editor

Add a new vegetation group and call it something appropriate (like grass).

Pic11: Adding a Vegetation group

Click the Add Vegetation Object (first button) to add a vegetation object to this category.

Pic12: Adding a vegetation object to the category

In the browse dialog, go to your folder where you saved the asset and select both grass assets:

• <Your_Project>\Assets\Objects\tutorial\vegetation\02\grass\merged_mesh\tutorial_merged_mesh_a
• <Your_Project>\Assets\Objects\tutorial\vegetation\02\grass\merged_mesh\tutorial_merged_mesh_b

Now highlight the object you just added to the category to select it, and you can perform the one of the following operations:

• Enable the Paint Objects button to paint down lots of instances your bush asset, or
• To be more precise, do not select the Paint Objects button (so it's not active) and on the terrain press Shift+LMB to place only 1 instance.

Activating Merged Mesh

Right now the Merged Mesh system is not activated for this category and our painted assets are static.

To activate this feature, inside the Vegetation Editor, click on your grass category or the item within and activate AutoMerged. Your grass field should now be ready and activated to bend with the wind & breeze generation.

Pic13: Static grass field

Pic14: Physicalized grass field

You are now able to change some additional values as long as this system is active to influence their behavior.

Breeze Generation

Tied to the physicalization of our Merged Mesh system is our Breeze Generation feature. This allows us to add randomized breeze forces to the global Wind vector. When activated, this system spawns Physics Proxies boxes and moves them along the surface of the terrain (following the wind vector direction) affecting only vegetation objects with Merged Mesh active.

To activate it, go to the Tools menu -> Level Editor -> level settings.

Within EnvState, we have our Breeze generation section. Enable the check box to activate the Breeze generation system. Make sure to also have a vaule > 0 in any of the the wind vector inputs (XYZ).

Pic15: Breeze generation check-box activated, under the highlighted directional wind vector

You should now be able to see your grass field being affected by this breeze feature.

There are several more parameters to this system for more control.

Debug Information

The easiest way to get instant feedback from the Merged Mesh system about how the breeze is interacting with the vegetation, is to enable the physics debug view: p_draw_helpers=1. This will render the proxies of all your geometry as usual, and additionally it will display the breeze elements as simple cubes running across the terrain.

Pic16: P_draw_Helpers=1 (red boxes are the simulated breeze proxies)

Below is a table of the available debug modes you can enable to inspect the merged mesh system.

e_MergedMeshesDebug=1

This offers a simple overview of the merged mesh system that gets appended to the r_displayinfo = 1 help text. The text displays information about how many active nodes (sectors) instances, spines and mesh data both in (kb) among other information.

e_MergedMeshesDebug=2

Using this debug view mode (e_MergedMeshesDebug=2) offers the most information as to how the system works from a user standpoint. The Red text down the left side of the screen lists the current states of all the merged mesh sectors.

Pic17: Custom level, with Merged Mesh grass assets added and e_MergedMeshesDebug=2 activated to see the clusters

Pic18: Sector info for e_MergedMeshesDebug=2

The next part covers the bounding boxes that are represented in this view. Here is a simplified view, where an empty level with lots of MM grass objects are placed down.

Pic19: Top down view with only the merged mesh grass in view.

Yellow boxes: These are the Sectors that represent a Merged Mesh group. The cell size is 16m x 16m. As soon as you place down one vegetation item (with merged meshes active), this starts a sector automatically.

Red and Green Boxes: Below the Yellow boxes closer to the ground, we have some smaller boxes either red (LOD0) or green (LOD1 and above). These are internal to the Yellow sectors. These will cover the limit of the bounding box of the actual placed vegetation items. If the cell is completely filled, it will be of full 16m x 16m size. But if you only cover a small section of the sector, these red / green boxes will cover just that section. See pic21 further down.

Sector debug Information: Now we are talking about the text that is associated with each sector. Each sector has this information of about itself. You should find this at the center of each sector.

Pic20: Sector debug info

ch (Materials per Sector)

This information tells you how many different materials are within this sector. To continue lets reduce down the amount of vegetation on screen to see whats actually happening.

First off, we have only placed down two grass blades in this sector. For example, note how the red bounding box just covers their size limits (bounding box) within the 16m yellow sector in Pic21. In the highlighted info box, see how the ch value is 1. This represents how many active materials there are in this sector.

Duplicate this grass object in the vegetation tool, since we want to use the material override parameter in properties with another material. Once the new material is applied onto another instance of the same geometry, the ch count will increase by one (same geometry, 2x materials). The same increase will happen if we add another different vegetation item, because that will also contain a different material.

Pic21: Simplified view of the sector with 2 instances of the same vegetation item.

For reference, below we have a sample texture originally 2048 x 4096, with around 22 different plants all together. You can create an enormous variety of vegetation using merged meshes and one material, and keep performance as high as possible by sharing the same texture / material within a sector.
Pic22: Example texture for a grass group used in the above scene in Crysis 3

e_MergedMeshesDebug= 256

With this debug view, we can inspect any entities that interact with the merged meshes. Note the collider spheres around the wheels on the vehicles and the AI character that interact with the merged mesh vegetation.

Pic23: Debug view to display the collider geometry within assets that interact with the mm system.

e_MergedMeshesDebug=2080

This view mode allows you to view the rope's LOD state. The further away from the camera, the system automatically starts to deactivate the ropes (red) in favor of the disabled ropes (blue). Note how it's not a hard-line between the On/Off states, but gradually reduces the active ropes over distance until they are all disabled (Blue).

Pic24: e_MergedMeshesDebug=2080 activated to see the rope LOD state (red active, blue inactive)

Further Debugging Info

The following debug commands are also useful to keep in mind while you work with this system: