### Author:  [@jb4x](https://discourse.processing.org/u/jb4x)
#### Post date: [July 20, 2018, 5:59am UTC](https://discourse.processing.org/t/implements-an-interface-of-a-library/1928/2 "2018-07-20T05:59:18Z")
Hello,
When you implement an interface, you need to define some functions listed in the interface.
In that case, you need to define the 3 following functions in your class :
- public float x(float t);
- public float y(float t);
- public float z(float t);
For more explanations :
>
---
### Author:  [@vjjv](https://discourse.processing.org/u/vjjv)
#### Post date: [July 20, 2018, 6:01am UTC](https://discourse.processing.org/t/implements-an-interface-of-a-library/1928/3 "2018-07-20T06:01:51Z")
some like this ?
maybe need also some information about this library…
```auto
import shapes3d.*;
import shapes3d.animation.*;
import shapes3d.utils.*;
I_PathGen[] pathh;
PathTube path;
Points points;
Tube tube;
PeasyCam cam;
void setup() {
size(600, 600, P3D);
pathh = new I_PathGen[20];
pathh[0] = new Points(0, 0,0);
pathh[0].x(1000);
pathh[0].y(100);
pathh[0].z(100);
path = new PathTube(this, pathh[0], 5, 300, 10, false);
path.fill(color(0, 255, 0), S3D.E_CAP);
}
void draw() {
background(0);
path.draw();
}
class Points implements I_PathGen {
float xx, yy, zz;
Points (float _x, float _y, float _z){
xx = _x;
yy = _y;
zz = _z;
}
public float x(float t){
return t;
}
public float y(float t){
return t;
}
public float z(float t){
return t;
}
}
```
---
### Author:  [@jb4x](https://discourse.processing.org/u/jb4x)
#### Post date: [July 20, 2018, 6:05am UTC](https://discourse.processing.org/t/implements-an-interface-of-a-library/1928/4 "2018-07-20T06:05:31Z")
Yep, looks good to me.
---
### Author:  [@vjjv](https://discourse.processing.org/u/vjjv)
#### Post date: [July 20, 2018, 6:09am UTC](https://discourse.processing.org/t/implements-an-interface-of-a-library/1928/5 "2018-07-20T06:09:03Z")
thanks. but still dont understand. i just wanna connect two points with a tube… but i dont find any example. this is ok?
```auto
class Points implements I_PathGen {
float xx, yy, zz;
Points (float _x, float _y, float _z){
xx = _x;
yy = _y;
zz = _z;
}
public float x(float t){
t = xx;
return t;
}
public float y(float t){
t = yy;
return t;
}
public float z(float t){
t = zz;
return t;
}
}
```
cos i expected to set a point but this dont display anything
---
### Author:  [@jb4x](https://discourse.processing.org/u/jb4x)
#### Post date: [July 20, 2018, 6:13am UTC](https://discourse.processing.org/t/implements-an-interface-of-a-library/1928/6 "2018-07-20T06:13:18Z")
I don’t know the library so I can’t be 100% sure but I don’t think that you need to set all the points manually.
The 3 functions x, y, and z are the equations that defines the shape of your path.
So when you write :
```auto
public float x(float t){
return t;
}
public float y(float t){
return t;
}
public float z(float t){
return t;
}
```
You are actually building a straight path that follows :
x(t) = t
y(t) = t
z(t) = t
I’m afraid I can’t really help more than that
---
### Author:  [@GoToLoop](https://discourse.processing.org/u/GoToLoop)
#### Post date: [July 20, 2018, 6:13am UTC](https://discourse.processing.org/t/implements-an-interface-of-a-library/1928/7 "2018-07-20T06:13:24Z")
> [@vjjv](#):
>
> ```auto
> float x(float t) {
> t = xx;
> return t;
> }
>
> ```
Parameters die along its function, so it’s useless to re-assign them! 😐
I believe you were meant to assign the **x()**'s _t_ parameter to the Points::_xx_ field instead: `xx = t;` 🤔
```auto
@Override float x(final float t) {
return xx = t;
}
```
---
### Author:  [@vjjv](https://discourse.processing.org/u/vjjv)
#### Post date: [July 20, 2018, 6:21am UTC](https://discourse.processing.org/t/implements-an-interface-of-a-library/1928/8 "2018-07-20T06:21:31Z")
```auto
import shapes3d.*;
import shapes3d.animation.*;
import shapes3d.utils.*;
I_PathGen[] pathh;
PathTube path;
Points points;
Tube tube;
void setup() {
size(600, 600, P3D);
pathh = new I_PathGen[20];
pathh[0] = new Points(2, 500, 6);
path = new PathTube(this, pathh[0], 50, 300, 10, false);
path.fill(color(0, 255, 0), S3D.E_CAP);
}
void draw() {
background(0);
translate(width/2, height/2);
path.draw();
}
class Points implements I_PathGen {
float xx, yy, zz;
Points (float _x, float _y, float _z){
xx = _x;
yy = _y;
zz = _z;
}
@Override float x(final float t) {
return xx = t;
}
@Override float y(final float t) {
return yy = t;
}
@Override float z(final float t) {
return zz = t;
}
}
```
try this and this is the result… dont know, im so lost…
---
### Author:  [@kfrajer](https://discourse.processing.org/u/kfrajer)
#### Post date: [July 20, 2018, 6:38pm UTC](https://discourse.processing.org/t/implements-an-interface-of-a-library/1928/9 "2018-07-20T18:38:51Z")
Did you check the documentation?
Lib page: [http://www.lagers.org.uk/s3d4p/index.html](http://www.lagers.org.uk/s3d4p/index.html)
Doc: [http://www.lagers.org.uk/s3d4p/ref/classshapes3d\_1\_1\_path\_tube.html](http://www.lagers.org.uk/s3d4p/ref/classshapes3d_1_1_path_tube.html)
What do you want to do?
Kf
---
### Author:  [@vjjv](https://discourse.processing.org/u/vjjv)
#### Post date: [July 21, 2018, 4:06am UTC](https://discourse.processing.org/t/implements-an-interface-of-a-library/1928/10 "2018-07-21T04:06:07Z")
I want to connect two points with a tube. first in a rect line, later, generate a spline or bezier curve