**We will analyze which basic properties solids have using `box` solid.**
*Basic properties:*
1.`opacity` - It is set in `float`. It takes on values from 0 to 1, which represent percents of solid opacity. It's initial value is 1.
2.`color` - It can be specified as `Int`, `String`, or as three `Ubytes`, which represent color in `rgb`. Elementally, the solid will have `green` color.
3.`rotation` - it's the point, which sets rotations along axes. Initially, the value is `Point3D(0, 0, 0)`. Changing `x` coordinate of the point, you make pivot around `x axis`. The same for other coordinates: changing `y` - pivot around `y axis`, changing `z` - pivot around `z axis`.
4. position, which is given by values `x`, `y`, `z`. Initial values are `x = 0`, `y = 0`, `z = 0`. The coordinate system is Cartesian. It's elemental position is this - vertical `y` axis and horizontal `Oxz` plane.
Let's see how properties are set in solids.
The `small box` will have elemental values of properties. If you don't set properties, it will have the same `position`, `color`, `rotation`, and `opacity` values.
***You can see that `box` take four values. Later, we will discuss what they do in more detail. Now, it does not really matter.***
```kotlin
box(10, 10, 10, name = "small box"){
x = 0
y = 0
z = 0
opacity = 1 //100% opacity
color("red") //as string
rotation = Point3D(0, 0, 0)
}
```
The `big box` will have properties with custom values.
```kotlin
box(40, 40, 40, name = "big box"){
x = 20
y = 10
z = 60
opacity = 0.5 //50% opacity
color(0u, 179u, 179u) //color in rgb
rotation = Point3D(60, 80, 0)
}
```
If we compare these boxes, we will see all differences.
As it takes such values as `upperRadius`, `startAngle`, `angle`, `cone` can build not only usual cones, but also cone segments. Initially, `upperRadius` will have `0.0` value, `startAngle` - `0f`, `angle` - `PI2`, so if you don't set them, you'll get just a simple cone.
Setting `upperRadius`, you make a frustum cone, since it sets a radius of the upper base of a cone. Set `startAngle`, and `angle` let to cut off segments by planes perpendicular to the base. `startAngle` - an angle, starting with which segment will be left, `angle` - an angle of cone, which will be set from `startAngle`.
Let's build a classic cone:
```kotlin
cone(60, 80, name = "cone") {
color("beige")
}
```
First of all, we have to try to build a frustum cone:
```kotlin
cone(60, 80, name = "cone") {
color(0u, 40u, 0u)
}
```
Now, we need to make a try to build a cone segment:
```kotlin
cone(60, 80, angle = PI, name = "cone") {
color(0u, 0u, 200u)
}
```
Finally, the segment of frustum cone is left for a try:
This solid is set by seven values:`bottomOuterRadius`, `bottomInnerRadius`, `height`, `topOuterRadius`, `topInnerRadius`, `startAngle`, and `angle`.
In addition to `height`, `startAngle`, and `angle`, which work as they work in `cone`, there are some new values.
`bottomOuterRadius`, and `bottomInnerRadius` set properties of the bottom circle, `topOuterRadius`, `topInnerRadius` - of the upper circle. They have no initial value, so that means they have to be set.
Generally, `cone`, and `coneSurface` buildings work in the same way, it's possible to make `coneSurface`'s fragments as in `cone`
Let's build usual cone surface with almost all properties set:
```kotlin
coneSurface(60, 50, 30, 10, 100, name = "cone surface") {
color("red")
rotation = Point3D(2, 50, -9)
}
```
Now, let's create a cone surface and set all it's properties:
*`layer` is `MutableList` types variable. (here is a sentence with a description of the work of this function). *The amount of `layer`-s has to be more than one*
