# Absolute value of complex numbers in 3D plot

When I try to make a 3d plot with complex numbers in it, such as this one:

```
plot3d(1+x+abs(i*omega), (x,0,5), (omega,0,5), viewer='tachyon')
```

I get errors saying

```
TypeError: unable to coerce to a real number
```

On another one I got

```
TypeError: Unable to convert 0.0345000000000000*I to float
```

Why is this happening?

EDIT:
Thanks for *slelievre*, lambda makes minimal example work. However, the original problem (I wanted to plot frequency responses) gives another error. Here is the original problem:

```
G_do_ideal_qn = -31.6656111462951*(0.0345000000000000*I*omega - 359.196869250000)/(-0.000389160000000000*omega^2 + 1.03531167486000*I*omega + 180.342274500000)
```

Tried to plot with

```
plot3d(lambda omega, V_C: 20*log(abs(G_do_ideal_qn), 10), (omega, 10, 100e3), (V_C, 0, 400))
```

Gives error

```
TypeError: unable to simplify to float approximation
```