I knew that it was too easy.
We received some new plan from our client.
and this time, polylines are not "connected" to block, but to point with CODE_CH1 attribute.
could you modify your routine to obtain the length for each polyline.
there are several layer and it's important to keep the length separated
(for example: caniveau = gutter ; enterre = buried; ...)
it's not the same team who will make the construction