Hey. I've been watching a lot of Gojira videos, and they have a very versatile repertoire or techniques. I need 2 of them explained lol. You can hear this especially on FMTS, in songs, and if you watch, they PM top 3/every string and very fast & tightly sweep down. I just cant seem to get that sound when i do it, and tips?
Another thing, they tremolo pick octave chords. How should I approach this, just start slow and work my way up to speed?
With the first one, tilt your pick to the side then mute all the strings with your fretting hand and scrape your pick from the 1st fret to the 5th (or 6th) fret. That is how you get that sound: example the outro to Ocean Planet. The tremolo picking of octave chords is a simple one, just practice it, it comes easy with a little bit of practice.
Dig a tunnel of light through ignorant walls
im not familiar with the band but the first technique you described sounds alot like a rake
with is mot palm muted but muted with your fretting hand and you basically rake down the strings it might not be the same tecnique but its worth a try

as for tremolo picking chords you know what to do
Hey! Gojira is an amazing band, indeed. That first technique you mentioned is one I've seen as well in several of their videos and as seeing them live. All it is is just a rake with your pick from the highest e string to the low E string. Gojira has a song lesson floating around somewhere where it shows him going over it. This is it, actually: http://www.youtube.com/watch?v=srF2iStKVtc

Also, I would just practice your strumming speed to a metronome and build your way up to speed so you can tremolo pick the octave and build up the acid in your right arm so you have endurance to play it.

Good luck!
I thought Gojira was a large, radioactive lizard who was fond of stomping Tokyo flat.
It is, but it's also an awesome French metal band.
[Gibson Explorer]
[Ibanez RG1XXV]
[Line6 PodHD]
[ENGL Retro Tube 100]
[Dunlop CryBaby]