# Revision history [back]

### 3D graphics bug?

Hi,

When I use the following code and I change the values of phi or theta, the previous red dot(point of projection) remains on the image and the new dot is added onto the image, giving two red dots. If I repeatedly change the values then more red dots appear. This problem does not occur if I get rid of the polygon inside the sphere. I'm not sure why this is happening...

S = sphere(size=10,color="yellow",opacity=0.5) north_pole = point3d((0,0,10), color="blue") r = 10 @interact def _(theta = slider(0,2pi,pi/20, default = pi/3, label="theta"), phi = slider(0,2pi,pi/20, default = pi/4, label="phi")): point_of_projection = point3d((rsin(theta)cos(phi),rsin(theta)sin(phi),r*cos(theta)), color="red")

## show(S + north_pole + point_of_projection)

 2 No.2 Revision Shashank 1887 ●28 ●47 ●82

### 3D graphics bug?

Hi,

When I use the following code and I change the values of phi or theta, the previous red dot(point of projection) remains on the image and the new dot is added onto the image, giving two red dots. If I repeatedly change the values then more red dots appear. This problem does not occur if I get rid of the polygon inside the sphere. I'm not sure why this is happening...

S = sphere(size=10,color="yellow",opacity=0.5)
north_pole = point3d((0,0,10), color="blue")
r = 10
@interact
def _(theta = slider(0,2pi,pi/20, slider(0,2*pi,pi/20, default = pi/3, label="theta"),
phi = slider(0,2pi,pi/20, slider(0,2*pi,pi/20, default = pi/4, label="phi")):
point_of_projection = point3d((rsin(theta)cos(phi),rsin(theta)sin(phi),r*cos(theta)), color="red")point3d((r*sin(theta)*cos(phi),r*sin(theta)*sin(phi),r*cos(theta)), color="red")
show(S + north_pole + point_of_projection)point_of_projection)


 3 No.3 Revision kcrisman 12082 ●39 ●126 ●246

### 3D graphics bug?

Hi,

When I use the following code and I change the values of phi or theta, the previous red dot(point of projection) remains on the image and the new dot is added onto the image, giving two red dots. If I repeatedly change the values then more red dots appear. This problem does not occur if I get rid of the polygon inside the sphere. I'm not sure why this is happening...

Works:

S = sphere(size=10,color="yellow",opacity=0.5)
north_pole = point3d((0,0,10), color="blue")
r = 10
@interact
def _(theta = slider(0,2*pi,pi/20, default = pi/3, label="theta"),
phi = slider(0,2*pi,pi/20, default = pi/4, label="phi")):
point_of_projection = point3d((r*sin(theta)*cos(phi),r*sin(theta)*sin(phi),r*cos(theta)), color="red")
show(S + north_pole + point_of_projection)


Doesn't work:

Z = Polyhedron([[2,3,3],[3,0,3],[2,6,1],[1,0,1],[6,7,2]])
Z_set_as_graphics = Z.show()
S = sphere(size=10,color="yellow",opacity=0.5)
north_pole = point3d((0,0,10), color="blue")
r = 10
@interact def _(theta = slider(0,2pi,pi/20, default = pi/3, label="theta"), phi = slider(0,2pi,pi/20, default = pi/4, label="phi")):
point_of_projection = point3d((rsin(theta)cos(phi),rsin(theta)sin(phi),r*cos(theta)), color="red")
show(Z_set_as_graphics + S + north_pole + point_of_projection)

 4 No.4 Revision kcrisman 12082 ●39 ●126 ●246

### 3D graphics bug?

Hi,

When I use the following code and I change the values of phi or theta, the previous red dot(point of projection) remains on the image and the new dot is added onto the image, giving two red dots. If I repeatedly change the values then more red dots appear. This problem does not occur if I get rid of the polygon inside the sphere. I'm not sure why this is happening...

Works:

S = sphere(size=10,color="yellow",opacity=0.5)
north_pole = point3d((0,0,10), color="blue")
r = 10
@interact
def _(theta = slider(0,2*pi,pi/20, default = pi/3, label="theta"),
phi = slider(0,2*pi,pi/20, default = pi/4, label="phi")):
point_of_projection = point3d((r*sin(theta)*cos(phi),r*sin(theta)*sin(phi),r*cos(theta)), color="red")
show(S + north_pole + point_of_projection)


Doesn't work:

Z = Polyhedron([[2,3,3],[3,0,3],[2,6,1],[1,0,1],[6,7,2]])
Z_set_as_graphics = Z.show()
S = sphere(size=10,color="yellow",opacity=0.5)
north_pole = point3d((0,0,10), color="blue")
r = 10
@interact  def _(theta = slider(0,2pi,pi/20, default = pi/3, label="theta"), phi = slider(0,2pi,pi/20, default = pi/4, label="phi")):
point_of_projection = point3d((rsin(theta)cos(phi),rsin(theta)sin(phi),r*cos(theta)), color="red")
show(Z_set_as_graphics + S + north_pole + point_of_projection)

 5 No.5 Revision kcrisman 12082 ●39 ●126 ●246

### 3D graphics bug?

Hi,

When I use the following code and I change the values of phi or theta, the previous red dot(point of projection) remains on the image and the new dot is added onto the image, giving two red dots. If I repeatedly change the values then more red dots appear. This problem does not occur if I get rid of the polygon inside the sphere. I'm not sure why this is happening...

Works:

S = sphere(size=10,color="yellow",opacity=0.5)
north_pole = point3d((0,0,10), color="blue")
r = 10
@interact
def _(theta = slider(0,2*pi,pi/20, default = pi/3, label="theta"),
phi = slider(0,2*pi,pi/20, default = pi/4, label="phi")):
point_of_projection = point3d((r*sin(theta)*cos(phi),r*sin(theta)*sin(phi),r*cos(theta)), color="red")
show(S + north_pole + point_of_projection)


Doesn't work:

Z = Polyhedron([[2,3,3],[3,0,3],[2,6,1],[1,0,1],[6,7,2]])
Z_set_as_graphics = Z.show()
S = sphere(size=10,color="yellow",opacity=0.5)
north_pole = point3d((0,0,10), color="blue")
r = 10
@interact
def _(theta = slider(0,2pi,pi/20, slider(0,2*pi,pi/20, default = pi/3, label="theta"), phi = slider(0,2pi,pi/20, slider(0,2*pi,pi/20, default = pi/4, label="phi")):
point_of_projection = point3d((rsin(theta)cos(phi),rsin(theta)sin(phi),r*cos(theta)), point3d((r*sin(theta)*cos(phi),r*sin(theta)*sin(phi),r*cos(theta)), color="red")
show(Z_set_as_graphics + S + north_pole + point_of_projection)