hi everyone
I'm not good at pure data.but I need a complicated piano instrument patch for my school project.but the patch will not be sampled.I will adapt the patch for android.its very important and hurry for me.please help me.

Yop,

1st you should post this kinda topic in the 'technical issues' section, imho.
2nd you should be much more explicit when asking for help. Did your teacher post a document explaining what the requirements are ? Maybe could you link it here.

Nau

My teacher didn't explain the requirements.But I think,my patch have to include filter,env. generator ... for piano or karplus-strong piano can be enough for me.I will enter the values of midi for piano and dac~ object will give me sound of the note.

this could be a good place to start:
http://en.flossmanuals.net/pure-data/audio-tutorials/simple-synth/

patches available here:
http://puredata.hurleur.com/attachment.php?item=2944

thank you for your posting.
but I need one thing more.That's the parameters of piano.for exemple,what's the waveform of piano or what's the parameters of envelope generator for piano.I couldn't find these anywhere on the internet.

There are some ways you could take advantage of piano samples without doing "pure sampling". Some older synths from the 80s (as well as cheap "toy" keyboards today) use a single cycle of a sample as its waveform due to limited memory. Since the transient attack of a sound is a vital part of recognizing the instrument, you could just sample it from the attack until it just starts its steady state, and then loop the single cycle that follows it. [susloop~] is probably the easiest way to go about it. You can figure out the length of the cycle in samples by dividing the sampling rate by the fundamental frequency. Then just use an amplitude and low-pass filter envelope to decay it (higher frequencies decay faster than low ones). You'd probably be better off using your ear to get the correct envelope parameters. An exponential decay will sound better than a linear one, though.

If you go the Karplus-Strong route, instead of initializing it with white noise, you could fill it with a sample of the transient. That way, it will start off with something closer to the piano's actual spectrum instead of just all possible frequencies.