How to translate an object on a straight line in vrealm?

I have tried to move a car on a straight line but the program gives error.I donot know what equation to give. t=1:60;

world=vrworld('my_car.wrl','new');
open (world);
set(world,'Description','my world')
fig=vrfigure(world);
car1=vrnode(world,'car');

for i=1:length(t)
    pause(0.01);
    car1.translation=t;
    vrdrawnow;
end