Category: Blender

Posted on

Batch rename objects in Blender

Today, we will tackle an essential aspect of 3D modeling in Blender – object naming.

It’s easy to lose track of your objects’ names, especially when you’re working on a complex project. All too often, we find ourselves with a sea of objects, each bearing an unhelpful name like ‘cube’, which doesn’t do much to tell us about their function or importance in the scene.

However, fear not! Blender offers a convenient tool for mass renaming of objects, allowing you to maintain order and clarity in your work. Let’s walk through the steps.

Firstly, you need to select the objects you want to rename. If your objects are neatly organized in a collection, simply right-click on the collection and choose ‘Select Objects’. Alternatively, if you’re dealing with individual objects, click on the first object, hold down ‘Shift’, then click on the last object. This selects those two objects and all others in between.

With your objects selected, hit ‘Control’ and ‘F2’. This brings up the ‘Batch Rename’ dialogue box. Here, you’ll specify the current name string you want to change – in this case, ‘cube’ – and what you’d like to replace it with. Click ‘OK’, and voila! All your selected objects are now renamed, saving you from any future confusion.

If you ever forget the shortcut, remember that you can always find the ‘Batch Rename’ option under the ‘Edit’ menu.

That wraps up today’s tutorial! We hope you found this helpful in managing your 3D workspace. Thanks for watching and remember to subscribe for more quick and easy Blender tips. Until next time, this is One Minute Video Tutorials.com, making your Blender journey a breeze, one minute at a time.

Posted on

Render a folder full of STL files to PNG images

I wanted to create images out of all the STL-files I had 3D-printed so far. Here is a script that automates the process using Blender.

import bpy
import os
import math
from bpy_extras.object_utils import world_to_camera_view

def clear_scene():
    bpy.ops.object.select_all(action='SELECT')
    bpy.ops.object.delete()

def setup_camera_light():
    bpy.ops.object.camera_add(location=(0, -10, 5))
    camera = bpy.context.active_object
    camera.rotation_euler = (1.0, 0, 0)
    bpy.context.scene.camera = camera

    bpy.ops.object.light_add(type='SUN', align='WORLD', location=(0, 0, 10))
    light = bpy.context.active_object
    light.rotation_euler = (1.0, 0, 0)

def create_red_material():
    red_material = bpy.data.materials.new(name="RedMaterial")
    red_material.use_nodes = True
    red_material.node_tree.nodes["Principled BSDF"].inputs["Base Color"].default_value = (1, 0, 0, 1)
    return red_material



from mathutils import Vector

def set_camera_position(camera, obj):
    bound_box = obj.bound_box
    min_x, max_x = min(v[0] for v in bound_box), max(v[0] for v in bound_box)
    min_y, max_y = min(v[1] for v in bound_box), max(v[1] for v in bound_box)
    min_z, max_z = min(v[2] for v in bound_box), max(v[2] for v in bound_box)
    
    # Calculate object dimensions
    width = max_x - min_x
    height = max_y - min_y
    depth = max_z - min_z

    # Calculate object center
    center_x = min_x + (width / 2)
    center_y = min_y + (height / 2)
    center_z = min_z + (depth / 2)

    # Calculate distance from camera to object center
    distance = max(width, height, depth) * 2.5  # Increase the multiplier from 2 to 2.5

    # Set camera location and rotation
    camera.location = (center_x, center_y - distance, center_z + (distance / 2))
    camera.rotation_euler = (math.radians(60), 0, 0)




def import_stl_and_render(input_path, output_path):
    clear_scene()
    setup_camera_light()

    bpy.ops.import_mesh.stl(filepath=input_path)
    obj = bpy.context.selected_objects[0]

    # Set camera position based on object bounding box
    camera = bpy.context.scene.objects['Camera']
    set_camera_position(camera, obj)
    
    # Apply red material to the object
    red_material = create_red_material()
    if len(obj.data.materials) == 0:
        obj.data.materials.append(red_material)
    else:
        obj.data.materials[0] = red_material

    # Set render settings
    bpy.context.scene.render.image_settings.file_format = 'PNG'
    bpy.context.scene.render.filepath = output_path
    bpy.ops.render.render(write_still=True)
    
     # Set transparent background
    bpy.context.scene.render.film_transparent = True

    # Set render settings
    bpy.context.scene.render.image_settings.file_format = 'PNG'
    bpy.context.scene.render.filepath = output_path
    bpy.ops.render.render(write_still=True)

def render_stl_images(input_folder, output_folder):
    for root, _, files in os.walk(input_folder):
        for file in files:
            if file.lower().endswith(".stl"):
                input_path = os.path.join(root, file)
                output_file = os.path.splitext(file)[0] + ".png"
                output_path = os.path.join(output_folder, output_file)

                import_stl_and_render(input_path, output_path)

if __name__ == "__main__":

    if __name__ == "__main__":
        input_folder = "3D Prints"
        output_folder = "/outputSTL"

    if not os.path.exists(output_folder):
        os.makedirs(output_folder)

    try:
        render_stl_images(input_folder, output_folder)
    except Exception as e:
        print(f"Error: {e}")

How to use:

Save the script in a python file. You can call it for example renderSTL.py. Change the input and output folders in the script to fit your situation.

Make sure you have Blender in PATH so that you can run it by simply typing “Blender” in a command prompt. If you don’t have it in PATH, open “enviroments variables” and edit the “PATH” variable under “system”. Add the path to your Blender installation as a new path.

Open up a command line in the folder which has the proper path to your STL root folder and paste this command in:
blender –background –factory-startup –python renderSTL.py

Blender should now render images out of all your STL files in the background and save them into the output folder.

Posted on

The New Pose Library Workflow in Blender

Here’s how to work with the Blender 3.4 pose library and assets browser:

Create the pose you need in pose mode. Select the bones that are required for the pose.

Save poses (still in pose mode) from the right side toolbar’s “animation” tab by clicking “Create Pose Asset”:

You can name the pose from the F9 operator dialogue.

You only need one pose for each side, since the poses can be flipped with “Flip Pose”.

Simply click on a pose thumbnail to apply it.

You can also right click on a thumbnail to select all the pose bones.

You can click and drag on a pose thumbnail to mix between to poses.

The thumbnail from the pose is rendered from the active camera. You can later change it from the Asset Browser window if needed from the “generate preview” button:

If you want to create a global “user library”, save the .blend file in the Assets directory. By default it’s in Windows: C:\Users\myusername\Documents\Blender\Assets\

It should now show up under “user library” in the assets browser, also for any new .blend files that you create.

You can save as many files as you need to the Assets folder, and each one of them will show up in the Assets panel under “user assets”

Posted on

Anyone can try NeRF now with a free app!

The 3D industry has been buzzing about Nvidia’s Instant NeRF (which stands for neural radiance fields) ever since they published their first demo video.

This technology has since been in rapid development and we now have a free iPhone app called Luma AI that anyone can use to capture NeRFs.

I tested the app with a toy robot, here’s a automatically generated video of the result:

The amazing thing about NeRF renders is that they can handle light reflections and bounces in a very realistic manner. This makes it a good fit for VFX work. We can also export a textured 3D-model from the Luma AI app, but it’s not as impressive as rendering with NeRFs. It’s still quite good compared to a basic photogrammetry process, especially considering that the surface of our object was quite reflective. Here’s a screenshot from Blender:

Here is how the mesh looks like (very dense):

Here’s another cool shot from a Robotime Ball Parkour toy:

@oneminutevideotutorial

Wow! NeRFs are going to be great for displaying products like this!

♬ original sound – user635578337916 –
Posted on

Blender keyboard shortcuts for working with nodes

Being able to work efficiently with different kinds of nodes in Blender is becoming increasingly important. These basic node related keyboard shortcuts should work in all of the Node editors in Blender including material nodes, the compositor and geometry nodes.

Add new node: shift+A

Just like you can add new objects with shift+a, the same shortcut also works for adding new nodes. If you want to immediately enter the search mode, read about the next shortcut below.

Add new node and search immediately: shift+A, then S

If you want to search for the name of the node instead of browsing through the categories, hit s immediately after hitting shift+a and it will take you to the search bar.

Disable a node: M

Sometimes you just want to see the results of a node tree without a certain node. In that case you can easily mute a node by selecting it and hitting M on your keyboard.

Delete a node: X

Just like you would expect, hitting X on the keyboard will delete the selected node(s).

Delete with reconnect: ctrl+X

If you want to delete a node in the middle of a node tree and automatically connect the node that came before the deleted node to the node where the deleted node was connected to, simply hit ctrl+X to delete the node from between.

Backdrop Zoom: V and alt+V

If you need to zoom out of the backdrop image to see it completely, just hit V on the keyboard. Zoom in by pressing alt+V.

Duplicate a node: shift+D

To make a duplicate of the selected node(s), just hit shift+D on the keyboard.

Connect a node to the viewer: ctrl+shift+leftclick

If you want to quickly connect a node’s output to the viewer node to see the result of the node, just hold down shift and control and left-click on the node you want to connect.

Cut a node connection: ctrl+rightclick-drag

If you want to cut a node connection, hold down control and the right mouse button and drag over the connection line.

Collapse node: H

Sometimes you want to collapse a node so that it takes less space. To do that, simply select the node and hit H on your keyboard and the node inputs will no longer be visible. If you want to reopen a collapsed node, simply hit H again.

Create node group: ctrl+G

Grouping nodes together allows you to simplify your node trees. By grouping several nodes together it is like combining them so that they appear to be just a single node. Simply select the nodes that you want to group together and hit ctrl+G. Note that all node types cannot be grouped together. For example you can’t put the “render layers” node in a node group.

Enter or exit node group: tab

After grouping nodes, Blender will automatically take you inside the group. To exit the node group, press tab on the keyboard. Similarly, to enter a node group, select the group and press tab.

Posted on

Basics of Using Cryptomatte in Blender 2.93

In the buttons area (on the right side of the interface), select the “View layer properties” tab.

Under “cryptomatte” turn on “object”, “material” or “asset”. I like “asset” since it let’s me select entire rigs that consist of several parts.

Go to the “compositing” workspace.

Turn on “use nodes”.

Add a viewer node with shift+a –> output –> viewer.

Add the cryptomatte node from Matte –> Cryptomatte.

Connect the image output from the render layers node to the image input of the Cryptomatte node. Connect the “pick” output from the Cryptomatte node to the image input of the viewer node. Render the scene (keyboard shortcut F12).

You should now see different matte colors that identify different assets in your render layer. Use the + button to access the eyedropper tool and select as many assets as you need for the matte you are building.

To see the actual matte, you can plug the “matte” output from the Cryptomatte node to the viewer.

Now you have a matte that you can use in various way when you are compositing. As a simple example, you could color correct the matted area by combining two copies of the input image with the “AlphaOver” node while using the matte as the factor. Then simply drop a color correction node like RGB curves between the bottom image connection.