How to set camera location in the scene while pointing towards an object with a fixed distance

Question

I want to position the camera around an object using Blender's Python API. Assuming that an object is centered at (0, 0, 0), I want to move the camera around it given a set of known (x, y, z) coordinate values while keeping its focus on the point (0, 0, 0) and its distance to middle of the object to be dist, a constant. I wonder how I can do that in Python?

As a matter of fact that should be easy even if you don't, we can calculate distance from to known points (Camera & Origin). Give me a few, I'll post an answer to this. — Rick Riggs, Feb 08 '18 at 21:56

score 4 · Accepted Answer · edited Dec 03 '20 at 12:22

The next function will rotate the camera towards the focus point. And then place the camera at a certain distance. The location of camera will only change along the direct line with the focus point.

import bpy
import mathutils
def update_camera(camera, focus_point=mathutils.Vector((0.0, 0.0, 0.0)), distance=10.0):
    """
    Focus the camera to a focus point and place the camera at a specific distance from that
    focus point. The camera stays in a direct line with the focus point.
:param camera: the camera object
:type camera: bpy.types.object
:param focus_point: the point to focus on (default=``mathutils.Vector((0.0, 0.0, 0.0))``)
:type focus_point: mathutils.Vector
:param distance: the distance to keep to the focus point (default=``10.0``)
:type distance: float
&quot;&quot;&quot;
looking_direction = camera.location - focus_point
rot_quat = looking_direction.to_track_quat('Z', 'Y')

camera.rotation_euler = rot_quat.to_euler()
# Use * instead of @ for Blender &lt;2.8
camera.location = rot_quat @ mathutils.Vector((0.0, 0.0, distance))


update_camera(bpy.data.objects['Camera'])

I just wanted to point out that this answer is also useful for (re-)orienting lights as well!!! It's just a matter of passing a light object in the camera variable. Thanks to J Bakker!!! — user2734434, Feb 07 '21 at 15:12

score 1 · Answer 2 · edited Dec 12 '20 at 18:11

Shift + A >> E >> P

Set X Location to 1.00000

Add another Empty (it will automatically be named 'Empty.001')

Shift + A >> E >> P

Now add a Camera

Shift + A >> E >> P

Position the Camera as follows:

[1.00000, 0.00000, 0.00000]

Rotate the Angles as follows:

90°, 0°, 90°

With the Camera still selected...

Shift + Select the First Empty >> Ctrl + P >> K (Object (Keep Transform))

Next select only the first Empty and add a Track To Modifier

Then set the Target to: Empty.001

Then set To to: -X

Here's the Python Code to do basically all of the same steps as above

import bpy
import math
bpy.ops.object.empty_add(type='PLAIN_AXES', view_align=False, location=(0, 0, 0), layers=(True, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False))
bpy.ops.object.empty_add(type='PLAIN_AXES', view_align=False, location=(0, 0, 0), layers=(True, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False))
newEmpties = []
for objName in bpy.data.objects.keys():
    if(len(objName.split("mpty")) > 1):
        newEmpties.append(objName)

print("-----")
print(len(newEmpties))
print("-----")
for i in newEmpties:
    print(i)
cnt = len(newEmpties)
myEmpties = []
myEmpties.append(newEmpties[cnt - 2])
myEmpties.append(newEmpties[cnt - 1])
e1 = bpy.data.objects[myEmpties[0]]
e2 = bpy.data.objects[myEmpties[1]]
e1.location.x = 1.0
bpy.ops.object.camera_add(view_align=True, enter_editmode=False, location=(0, 0, 0), rotation=(0.961699, 0.0122912, -0.897371), layers=(True, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False))
newCams = []
for objName in bpy.data.objects.keys():
    if(len(objName.split("amera")) > 1):
        newCams.append(objName)

myCam = bpy.data.objects[newCams[len(newCams) - 1]]
myCam.location.x = 1.0
myCam.rotation_euler.x = math.pi * 0.5
myCam.rotation_euler.z = math.pi * 0.5
bpy.ops.object.select_all(action='DESELECT')
myCam.select = True
e1.select = True
bpy.context.scene.objects.active = e1
bpy.ops.object.parent_set(type='OBJECT', keep_transform=True)
bpy.ops.object.constraint_add(type='TRACK_TO')
e1.constraints['Track To'].target = e2
e1.constraints['Track To'].track_axis = 'TRACK_NEGATIVE_X'
bpy.context.scene.objects.active = myCam
scene = bpy.data.scenes['Scene']
scene.camera = myCam

For Blender >2.8 (new python api)

import bpy
import math
def pointACamTo(toPoint, fromPoint):
    bpy.ops.object.empty_add(type='PLAIN_AXES', location=fromPoint)
    bpy.ops.object.empty_add(type='PLAIN_AXES', location=toPoint)
newEmpties = []
for objName in bpy.data.objects.keys():
    if(len(objName.split(&quot;mpty&quot;)) &gt; 1):
        newEmpties.append(objName)
#

print(&quot;-----&quot;)
print(len(newEmpties))
print(&quot;-----&quot;)
for i in newEmpties:
    print(i)

cnt = len(newEmpties)

myEmpties = []
myEmpties.append(newEmpties[cnt - 2])
myEmpties.append(newEmpties[cnt - 1])
e1 = bpy.data.objects[myEmpties[0]]
e2 = bpy.data.objects[myEmpties[1]]

e1.location.x = fromPoint[0]
e1.location.y = fromPoint[1]
e1.location.z = fromPoint[2]

bpy.ops.object.camera_add(align='VIEW', enter_editmode=False, location=(0, 0, 0), rotation=(0.961699, 0.0122912, -0.897371))

newCams = []
for objName in bpy.data.objects.keys():
    if(len(objName.split(&quot;amera&quot;)) &gt; 1):
        newCams.append(objName)
#
myCam = bpy.data.objects[newCams[len(newCams) - 1]]
#myCam.location.x = fromPoint[0]
myCam.location.x = fromPoint[0]
myCam.location.y = fromPoint[1]
myCam.location.z = fromPoint[2]

myCam.rotation_euler.x = math.pi * 0.5
myCam.rotation_euler.z = math.pi * 0.5

bpy.ops.object.select_all(action='DESELECT')
myCam.select = True
e1.select = True
#bpy.context.scene.objects.active = e1
# wrong, read-only bpy.context.active_object = e1

# select: eventually remove
# wrong, for multiple selection eventually: e1.select_set(True)
bpy.context.view_layer.objects.active = e1

bpy.ops.object.parent_set(type='OBJECT', keep_transform=True)

bpy.ops.object.constraint_add(type='TRACK_TO')
e1.constraints['Track To'].target = e2
e1.constraints['Track To'].track_axis = 'TRACK_NEGATIVE_X'

# as safety measure:
##deselectAllObjectsInScene()

# eventually remove
#bpy.context.scene.objects.active = myCam
bpy.context.view_layer.objects.active = myCam
scene = bpy.data.scenes['Scene']
scene.camera = myCam




#and run
pointACamTo([0,0,0], [2,2,2])

Now in a separate python script you can use a function like follows to position the camera to a point.

Here's an example of the result

How to set camera location in the scene while pointing towards an object with a fixed distance

2 Answers2

Linked