Vibration analysis scilab

Question

I have a problem to do a vibration analysis on scilab. to explain, I have to make a vibration analysis of an engine in 2d and then in 3D (see pictures)

3d graph I want to obtain

the 2d graph obtained

My basic file consists of a CVS with two columns, with time and acceleration. I used the fft function for the 2D graph, but for the 3D I don't know how to do it. The code for the 2D graph:

sample_rate=1/(Time(2)-Time(1));
N=max(size(Time));
freqfftDatas =[sample_rate*(0:(N/2))/N]';
FFT=fft(Datas(1:N));
n=max(size(freqfftDatas));
fftDatas =abs(FFT(1:n))*2/N;

plot(freqfftDatas, fftDatas);

I've read about waterfall, but I don't know how to relate it to my case.

If there are people familiar with scilab who could help me, I thank you!

Answer 1

For this kind of representation you have to use surf, here is an example with the sliding window FFT of a chirp like signal:

[t,u]=meshgrid(0:0.01:10,0:0.01:1);
y=sin((%pi*(t+u)).^2);
Y=fft(y,1,1);
clf
gcf().color_map=parulacolormap(128);
surf(abs(Y),"facecolor","interp")
gce().color_mode=-1