Welcome to my Retail Blockland tutorial of getting rid of your hud, thanks to 1529op, he found out how while i was in his server
Hit the Tilda key (~) for the console, then type in canvas.setcontent(noHudGui); and to get your hud back, type in the console canvas.setcontent(playGui);
Again, thanks go to 1529op for finding it out and telling me how while i was in his server