TypeError: Could not convert list item to float

[new_horizon]

Hi All,

I have created a virtual environment whereby a photographic car approaches the observer viewpoint and the degree of expansion of the object on approach is manipulated according to a Psychophysical procedure.

I am now trying to insert some distracter motion and have so far been successful in inserting some pedestrians on the sidewalks. I have created some other cars by inserting quads and wrapping a car image around them. However, after inserting the necessary commands into the procedure - I get the error message "TypeError: Could not convert list item to float".

I understand that there is a lot of code in my script, so I have included only the parts where the error and where I created the object "vehicledummy2" is occuring for now...

## Create Dummy Car Left Facing Side ##
dummy2carsize = [3.2, 1.65] # [ height, width ]
cardummyleft = viz.addTexture('Van Right Facing.tif')
vehicledummy2 = viz.addTexQuad(viz.WORLD,viz.MainScene,1) # 1m sq quad
vehicledummy2.texture(cardummyleft)
vehicledummy2.setScale(dummy2carsize[0],dummy2carsize[1],1) # Size to car width & height
vehicledummy2.setEuler(90,0,0)
vehicledummy2.setPosition(outofview)
vehicledummy2.appearance(viz.TEXMODULATE)# ----------------------------------------------#
# MOVE THE OBJECT FOR THE SPEC'D TIME #
# ----------------------------------------------#

def render_ball1(on_switch, Loom_level):
global select,rng,plgit, mlgit,prob, nv, trialsplt,nv_p,sgn,sgn_p,reverse, X_motion,Obs_rotn, L_inc,Min_loom,Obj_sz,Obj_scale, T_exp, Z_dist,Z_far, Speed
global Vert_screen, Aspect, Z_observer, pixelcm, pixeldg,Lpixels,selectM, remove
object1.setPosition(xobs,yobs,Z_dist)
theta_start = math.atan(Obj_sz/Z_dist)
theta_final = theta_start + Loom_level*T_exp
Rescale = theta_final/theta_start # zero shift if not a descent trial
if on_switch == 0:
Rescale = 1.0
Size_shift = vizact.size(Rescale*Obj_scale[0],Rescale*Obj_scale[1],1,T_exp,viz.TIME)
# Calculate random side motion.
side = [-0.5, 0.5, -1, 1]
updn = [-0.5, 0.5, -1, 1]
random.shuffle(side); random.shuffle(updn);
X_shift = X_motion[select]*side[0] # Use observer rotn instead
Y_shift = Y_motion[select]*updn[0] # Use observer rotn instead
#Pos_shift=vizact.goto(0*X_shift,0*Y_shift,Z_dist, T_exp,viz.TIME)
#print X_shift,Y_shift,Z_dist
#motion = vizact.parallel(Size_shift,Pos_shift)
cross1.visible(viz.OFF)
time1=viz.tick()
object1.visible(viz.ON)
time2=viz.tick()
male = viz.add('vcc_male.cfg')
male.setPosition(xobs+3, 0, Z_observer+25)
male.setEuler(0,0,0)
male.state(2)
m_walk = vizact.goto(xobs+3, 0, Z_observer+26, 0.25, viz.TIME)
m_walking_sequence = vizact.sequence(m_walk, remove)
male.addAction(m_walking_sequence)
female = viz.add('vcc_female.cfg')
female.setEuler(180,0,0)
female.state(2)
female.setPosition(xobs+4, 0, Z_observer+28)
f_walk = vizact.goto(xobs+4, 0, Z_observer+27, 0.25, viz.TIME)
f_walking_sequence = vizact.sequence(f_walk, remove)
female.addAction(f_walking_sequence)
female2 = viz.add('vcc_female.cfg')
female2.setEuler(180,0,0)
female2.state(1)
female2.setPosition(xobs-15, 0, Z_observer+80)
f_walk2 = vizact.goto(xobs-15, 0, Z_observer+80, 0.25, viz.TIME)
f_walking_sequence2 = vizact.sequence(f_walk2, remove)
female2.addAction(f_walking_sequence2)
#Add the models
vehicledummy2set = vizact.goto(xobs-1, 0, Z_observer+10)
vehicledummy2move = vizact.goto(xobs-1, 0, Z_observer+10, 0.25, viz.TIME)
vehicledummy2sequence = vizact.goto(vehicledummy2set, vehicledummy2move, remove)
vehicledummy2.addAction(vehicledummy2sequence)
# if selectM == 0:
view.goto(xobs,yobs,Z_observer,T_exp,viz.TIME)
# if selectM == 1:
# view.spinto(side[0],updn[0],0,Obs_rotn,T_exp,viz.TIME)
time3=viz.tick()
object1.add(Size_shift)
time4=viz.tick()
# print time1,time2,time3,time4

Obviously a number of these variables have been defined earlier in the script - can anyone shed any light on why this error message might be surfacing?

Thanks