Usage guide

This is a short introduction on how to use the SuperGrass Plug-In for 3d Studio Max. An italian version is available here. Thanks to 3D Cyborg

We start the first part of this guide with how to create a single blade and to show you what parameters have what influence on the appearance of a single blade. This is crucial to know since on more complicated structure you basically influence the variance on these parameters inside your lawn.

Step 1: How to create a single blade

We assume you have successfully installed the plug-in in your Max version and started your Max session now you should go to the object creation tab on the right and select the drop down menu. Open it and switch to SuperGrass. If you successfully selected it you will get a new tab with three buttons "Blade", "Bundle", "Lawn". In this part we concentrate on "Blade" so select "Blade"

Step 2: Wooow! What do all these parameters mean?

To understand the parameters it is probably best to have a look at the image above. The different colour lines connected to each parameters box show exactly what part of the blade or what visible appearance it controls. Sometimes two parameters can have an influence on a similar feature. For example in this case gravity and stiffness are somehow counteracting itself. Stiffness controls the internal tensile strength of the blade telling how strong the vertical growth rate is, while gravity pulls the blade into the opposite direction down to earth again.

Step 3: Still confused?

Are you still confused? Why not watch then our little video demonstration that shows the single blade generation. You can grab it here it is a zipped AVI and it is 2160 Kbytes big.

Step 4: How to create a single bundle

After we know how a single grass blade works it is time to move on to the more complex geometries. The next one is the grass bundle which consists of an arbitrary number of blades, usually in the range between two to five. So just select next the "Bundle" button on the top as displayed in the image. A new rollout should open with parameters.

Step 5: Understanding the parameters of a single grass bundle

As you might notice most of the parameters are identical with the one from the single grass blade. This is not very surprising since the bundle consists of a number of grass blades and the individual grass blades are controlled with the same parameters. You will also notice that for each of the blade parameters there is a variation or a min/max parameter. The variation controls how wide the variation between the individual grass blades in the bundle can be. For example a variation setting of 0.5 means there is a variation on this parameter up to 50% in both directions so either 50% lower or 50% higher. In the case of min/max the settings for each individual blade in the bundle will be between the minimum and maximum setting for this parameter. There are also two new parameters for the bundle that are not in the grass blade. The first one -- marked blue in the image to the left -- specifies how many blades should the bundle contain. Usually a number between three or five is sufficient for a realistic looking grass bundle. The second parameter -- marked green in the image to the left -- specifies the bending range of the blades in the bundle specified as a rotation angle in degrees. This helps to increase the variation of the blades inside the bundle and give an even more realistic looking effect.

Step 6: Still confused?

Are you still confused? Why not watch then our little video demonstration that shows the single grass bundle generation. You can grab it here it is a zipped AVI and it is 2920 Kbytes big.

Step 7: How to create a lawn patch

As we know hopefully understand both the single grass blades as well as grass bundles it is time to move on to start building our first grass lawn patch. For doing this we have to press the "Lawn" button as displayed in the image on the left to switch to the "Lawn"creation mode. A new rollout should open with parameters. We will deal with some the parameters later but first

Step 8: Specify the size of lawn patch

To specify the dimension and initial geometry of your lawn patch. Move your mouse into one of the viewports. We recommend to use the top view one. Then press and hold the left mouse button. When you now move your mouse a rectangle should appear as demonstrated in the left image. This controls the dimension of your lawn patch. It is similar to creating a Max standard Box object or rectangular shape. As soon as you are satisfied with the dimension just release the left mouse button and the lawn patch should appear. It will be filled up automatically with the specified number of grass blades or bundles as have been set for both the X and Y direction on the plane. Of course the size is not fully fixed yet you can always use the width and length control in the parameter rollout to change it.

Step 9: Lots of parameters again!

Do not panic! Most of these parameters you should already be aware of from the previous steps. As again they control parameters on the blades and the range of variations between the individual blades in the lawn patch. As you can see from the image on the left. The parameters are divided into three rollout or groups. The first one at the top specifies global parameters that effect the whole lawn structure. Some of them will be covered in more detail in the more advanced guides. The second rollout is only of relevance when you selected the blade option in the global settings. This will specify blade specific parameters that are used for the blades to fill up the lawn structure. The third rollout is only of relevance when you selected the bundle option in the global settings. In this case the lawn structure will not be filled up with individual blades but with grass bundles. Of course this produces a lot more geometry.
The first question you should answer yourself do you want the geometry stored into a single mesh object. This is the option single mesh (in the image marked with red). The default setting is on, since it is more resource friendly to the 3D Studio Max system by doing so and in most cases you do not want to have each individual blade or bundle stored as a separate mesh. However, it is possible to do so by unclicking that option. This might be useful if you have special animation needs and need full control on each blade.
The next thing to decide on is if you want single blades or bundles in your lawn patch. Single blades produces less geometry are therefore faster to interact and render. Grass bundles on the other hand produce a more denser structure.
If you are satisfied with your choice the next decision to take is on how dense your lawn should be -- how many blades or bundles it should contain. This is controlled by the # Blades X and # Blades Y parameters marked between the blue lines. A good rule of thumb is to have about at least one blade by every two units better would be one. So for example if your lawn patch is 107x112 units big. You should have at least 53 blades in X direction and 56 blades in Y direction (better would be 107 to 112). Of course you are free to use far less than that but your lawn patch might appear a bit empty or with large gaps, especially when viewed from above.
Another interesting parameter to be aware of is the one marked green in the image. The maximum blade length option sets an upper limit in the vertical growth direction of the blades. The upper limit will be set to the blade-length. Due to the variance some of the blades would grow taller than that. But when the maximum blade length option is set they can't therefore, they start to bend to compensate for that extra length.

Step 10: Still confused?

Are you still confused? Why not watch then our little video demonstration that shows the lawn patch generation. You can grab it here it is a zipped AVI and it is 8567 Kbytes big.