Hi everybody! My name is Isidro, and I am from Costa Rica. Some time ago I was trying to find out how to create realistic grass and plants for a university project, but I could not find anything. Later I learned how to do it, and now I have created a tutorial on the subject.
You can find this tutorial in the officialCommunity of Autodesk-Maya User
In this tutorial, I will describe how to create realistic 3d grass using Maya's Paint Effects. Here is the final image that we will create
First, we need to understand what grass looks like in reality. See this photo.
This photo contains many different colors, sizes, and types of grass. You will almost never have a single kind of grass in your scene, because in reality there are always other plants mixed in with the grass. There are some flowers, some weeds, some dried-out (dead) grasses, and so on. So, if you want realistic grass, you must use several different kinds of plants in your image. In addition, you must vary the size and color of your plants throughout the scene.
Take a close look at this photograph:
Notice how many different kinds of grass and other plants there are in this little space! There are also some pieces of wood mixed in. Also, observe the shadows in the grass:
The red arrows show how the shadows work, and the blue ones show where the light goes. You can see that the top of the grass gets plenty of light, and the bottom of the grass has dark, irregular shadows. Each stalk of grass casts a shadow on the ground and on its neighboring stalks. As a result, very little light reaches the ground. We need lots of contrast between the top and the bottom of the grass to produce a really realistic image. I am not saying that the individual shadows need to be very strong, just that there needs to be a distinct contrast between the tip of each stalk and the root. This gives the grass a sense of depth. Look at this series of images:
You can see how the shadows (the second image) are random and have many different sizes and shapes. In the third image you can see that the light is more uniform (mainly because the grass has uniform size). In places with strong light, we see strong shadows; but where the light is softer the shadows are softer and more transparent. This combination of soft, semi-transparent shadows and harsh shadows gives the image realism.
The first stage
Now that you understand how light and shadow work in a more theoretical sense, let's open Maya and start actually creating our image. This is the image we will create in this tutorial.