Blender (software): Difference between revisions

Retrieved from "https://wiki.davidl.me/view/Blender_(software)"

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 Blender is an open-source 3D modelling software.<br>
-It can be used for creating 3D models for games, 2D/3D animations, and even video games.<br>
+It can be used for creating 3D models for games, creating 2D/3D animations, and even creating video games.<br>
+==Getting Started==
+===Installation===
+;Windows
+[https://www.blender.org/download/ Direct Download]<br>
+From chocolatey:
+<pre>
+choco install blender
+</pre>
+;Ubuntu
+Blender is available on the Snap store
+<pre>
+sudo snap install blender --classic
+</pre>
-==Tutorials and Guides==
+==Modelling==
+===Geometry Nodes===
+[https://docs.blender.org/manual/en/latest/modeling/geometry_nodes/index.html Blender Manual Geometry Nodes]
+Geometry nodes allow you to procedurally modify the geometry of the object.
+Some things it can do include instancing of objects, moving vertices, and arithmetic.
+Note that Geometry nodes are available in Blender 2.92+ with some nodes introduced in 2.93 LTS.
+See some references:
+* [https://www.youtube.com/watch?v=Lb9tJhn9EHE Making grass by SouthernShotty]
+* [https://www.youtube.com/watch?v=TjGL4RjR13Q Making a raspberry by Bad Normals]
+* [https://www.youtube.com/watch?v=52UYqe3zdxQ Making a gumdrop by Blender Guru]
+==Materials and Shaders==
+Blender uses a node system for shader which let you composite different textures and BSDFS.
+===Bypass BSDF===
+If you wish to use a raw colors from a texture, bypassing materials altogether, you can directly attach a image texture node output to the material output.<br>
+For transparent textures, you will need a transparent BSDF node and a mix node with alpha connected to <code>mix.outputs["Fac"]</code> to achieve transparency.
+==Animations==
+==Rendering and Compositing==
+Press {{key press|F12}} to render.
+===Denoising===
+# In the view layer properties, check <code>Denoising Data</code>
+# Switch to the compositor layout.
+# Add a denoise node, under filter.
+# Attach the denoising normal, denoising albedo, and denoising depth.
+==Scripting==
+[https://docs.blender.org/api/current/index.html Blender Python API]
+===Getting Started===
+Blender supports scripting as an alternative means of interaction.
+Most things are available in the <code>bpy</code> module.
+See one of the following resources to get started:
+* [https://www.youtube.com/watch?v=XqX5wh4YeRw Python Crash Course for Blender! by Curtis Holt]
+===Meshes===
+<syntaxhighlight lang="python">
+vertices = [(-1, -1, 0), (1, -1, 0),
+            (-1, 1, 0), (1, 1, 0)]
+edges = [(0,1), (1,2), (2,3), (3,0)]
+faces = [(0,1,2), (1,2,3)]
+uvs = [(0, 0), (1, 0),
+       (0, 1), (1, 1)]
+# Create a new mesh
+new_mesh = bpy.data.meshes.new(mesh_name)
+new_mesh.from_pydata(vertices, edges, faces)
+new_mesh.update()
+# Add UVs
+uv_layer = new_mesh.uv_layers.new()
+for face in new_mesh.polygons:
+  for vert_idx, loop_idx in zip(face.vertices, face.loop_indices):
+    uv_layer.data[loop_idx].uv = uvs[vert_idx]
+</syntaxhighlight>
+===Materials===
+<syntaxhighlight lang="python">
+# Create a new material
+my_material = bpy.data.materials.new("My New Material")
+my_material.use_nodes = True
+# Add material to an object
+my_object.data.materials.append(my_material)
+</syntaxhighlight>
+====Images====
+<syntaxhighlight lang="python">
+# Add an image
+image_bpy = bpy.data.images.new("my_image", width=width, height=height, alpha=(channels==4), float_buffer=False)
+image_bpy.pixels = np.flipud(image_np).ravel()
+image_tex_node = my_material.node_tree.nodes.new("ShaderNodeTexImage")
+image_tex_node.image = image_bpy
+my_material.node_tree.links.new(image_tex_node.outputs['Color'], my_bsdf.inputs['Base Color'])
+</syntaxhighlight>
+===Saving scripts outside===
+See [https://b3d.interplanety.org/en/using-external-ide-pycharm-for-writing-blender-scripts/ using external ide] and [https://blender.stackexchange.com/questions/51074/how-to-run-a-python-script-external-to-blender-to-run-bpy-commands-in-blendersp run external scripts].
+By default, everything is stored in the <code>.blend</code> file including your custom scripts.
+If you want to store your scripts outside or use another IDE, you will need to have the script inside Blender call the script outside:
+<syntaxhighlight lang="python">
+import bpy
+filepath = bpy.path.abspath("//myscript.py")
+exec(compile(open(filepath).read(), filename, 'exec'))
+</syntaxhighlight>
+===Rendering===
+<syntaxhighlight lang="python">
+def render_to_file(filepath, width, height):
+    # Set device to GPU
+    bpy.context.scene.cycles.device = "GPU"
+    # Set resolution
+    bpy.context.scene.render.resolution_x = width
+    bpy.context.scene.render.resolution_y = height
+    bpy.context.scene.render.resolution_percentage = 100
+    # Set output file path
+    bpy.context.scene.render.filepath = filepath
+    # Do render
+    bpy.ops.render.render(write_still=True)
+</syntaxhighlight>
+===MVP matrices===
+[https://github.com/blender/blender/blob/v2.93.0/doc/python_api/examples/gpu.9.py Example python code]
+<syntaxhighlight lang="python">
+# Model matrix
+my_object.matrix_world
+# View matrix
+bpy.context.scene.camera.matrix_world.inverted()
+# Projection matrix
+projection_matrix = bpy.context.scene.camera.calc_matrix_camera(
+     bpy.context.evaluated_depsgraph_get(), x=WIDTH, y=HEIGHT)
+</syntaxhighlight>
+===Python Modules===
+To add modules, install them using pip to the <code>scripts/modules</code> directory of your Blender install:
+<pre>
+python3.9 -m pip install -t=scripts/modules $MODULE
+</pre>
+* If you installed blender using snap, you will need to create another scripts directory somewhere else.
+==Compiling Blender==
+See [https://wiki.blender.org/wiki/Building_Blender/Linux/Ubuntu https://wiki.blender.org/wiki/Building_Blender/Linux/Ubuntu],
+Note that Blender has a [https://github.com/blender/blender github mirror] which may be faster to clone.
+==Resources==
 * [https://www.youtube.com/playlist?list=PLjEaoINr3zgEq0u2MzVgAaHEBt--xLB6U Blender 2.8 Beginner Tutorial by Blender Guru]
+** This is an updated version of the famous donut tutorial
+** See [https://www.reddit.com/r/BlenderDoughnuts/ https://www.reddit.com/r/BlenderDoughnuts/]
+* [https://www.udemy.com/course/blendertutorial/ Complete Blender Creator: Learn 3D Modelling for Beginners (Udemy, $20)]