if (model.v>0)
    model.n_t = floor(2 * model.r / model.v / model.dt);
    if (model.n_t > options.max_t)
	if (model.n_t < options.max_t / 2)
	    t = model.dt:model.dt:options.max_t * model.dt;
	    model.delta_theta = pi / 180 / 2;	%approx.
	else
	    middle = model.dt * model.n_t / 2;
	    beg = middle - options.max_t * model.dt;
	    t = beg + model.dt:model.dt:middle;
	    model.delta_theta = atan((model.r - model.v * beg)) / 180;
	end
	model.n_t = options.max_t;
    else
	t = 0:model.dt:2 * model.r / model.v - model.dt;
    end
else
    t = 0:40 / model.n_t:40;
end