Reading the Scene with Python

Here is the moment scripting starts to feel useful. Instead of clicking around to find out what is in a scene, you ask Python to list it. Names, types, positions, real dimensions, counts. Anything you can see in the Outliner, you can read as data.

That matters when a scene grows. Checking thirty objects by eye is slow and unreliable. Checking three hundred with a loop takes no time at all, and it gives you a list you can sort, save or compare with a client’s drawing.

The loop that reads everything

bpy.context.scene.objects is the collection of objects in the current scene. Iterate over it and you have every object in turn; each one carries its own name, type, location and dimensions.

read_scene.py

# Read the scene like a table
import bpy

print("%-16s %-9s %-24s %s" % ("name", "type", "location", "dimensions (m)"))

for obj in bpy.context.scene.objects:
    loc = "(%5.2f, %5.2f, %5.2f)" % tuple(obj.location)
    dim = "(%5.2f, %5.2f, %5.2f)" % tuple(obj.dimensions)
    print("%-16s %-9s %-24s %s" % (obj.name, obj.type, loc, dim))

print("total objects:", len(bpy.context.scene.objects))
Script reading the whole scene object by object
One loop, and the whole scene becomes a table you can check, count and compare.
Text Editor close-up of the reading script
The script up close: a header line, then one loop over every object in the scene.

What each field tells you

  • obj.name – the name you see in the Outliner. Scripts make naming rules easy to keep.
  • obj.type – MESH, CAMERA, LIGHT, EMPTY and so on. Useful for filtering.
  • obj.location – where the object sits, in metres, on X, Y and Z.
  • obj.dimensions – the real bounding size of the object, after scale. This is the number you care about when a part must fit a machine or a printing plate.

The same idea works in the Python Console, which is perfect for a quick check before you commit anything to a file. Type a loop like the one below and Blender answers immediately:

Python Console reporting objects and dimensions
The same idea in the Python Console: every object, its type and its real size in metres.
Layout workspace with the objects the script reads
What the script is reading: five objects with names, positions and dimensions.
Outliner close-up of the five objects
The Outliner up close: the same five objects, in the order Python walks through them.

A real use: checking a scene against a list

Imagine a client sends a list of parts with dimensions. You build the scene from it, then run a script that prints every part next to its expected size. Mismatches stop being invisible: they show up as text, before anything is printed or shipped. That is an audit you can run in one second, on every revision, forever.

Next: the other side of the coin. Before you build from a list, you often want the scene empty. Clearing it properly is a one-liner, and there is a right way and a wrong way to do it.

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