we need to register an information only for the first step of a track entering in a volume. In particular, we need to calculate the angle of a particle entering in a bar of the DIRC.We already can calculate this angle, but at the moment we have as many angles as the steps inside the volume for each event. Instead we need of the angle of the first step only, so only one for each event.

Do you know how I can select with VMC the first step of a strack entering in a volume?

Thanks

Annalisa and Elisa]]>

You might want to have a look into the Mvd ProcessHits function

There you have

This is processed only at the first step, as you need it.

I hope this helps.

Ralf.]]>