By default Blender treats all surfaces as though they are double-sided, rendering meshes as though they have both a front and back face. It does this through backface rendering a process where front faces, those typically pointing away from an objects Origin, are duplicated and inverted to give the impression the surface is double-sided. In instances where meshes need to appear single-sided this behaviour can be disabled using Backface Culling.
Important: back-face culling is typically the default state surfaces are process and rendered thus two-sided surfaces, surfaces appearing solid front and back, are essentially a post-processed effect – a given original (and culled) surface and associated properties are duplicated and flipped to produce the two-sided (simple) effect. In this context neither side acts independently of the other so they can appear incorrectly shaded or shadowed (the back-side of a leaf should be shaded but is often drawn fully lit per the front-side). This latter problem can be addressed using a double-sided mesh.
The availability of Backface Culling depends on Viewport Shading – Solid, Look Dev or Rendered, and the Engine used to render everything on-screen – Eevee, Workbench or Cycles. What this essentially means is that Backface Culling is associated with Viewport Shading or Material setting, or as a Render property, the option to enable/disable the feature then being located in different places depending on the environment used.
Design note: because backface rendering is for all intents and purposes a surface property, Blender is not generating editable mesh structure to produce the effect, and this where the feature is enabled changes – it’s essentially not a ‘global’ property in a strict usability sense that one option or setting activates the effect for everything in all viewport shading or rendering environments.
The availability of Backface Culling depends on the environment being used, Viewport Shading and render Engine – shown above for example, in Rendered mode the Backface Culling option is not in Viewport Shading options.
Solid + Eevee
To enable or disable Backface Culling when Viewport Shading is set to Solid mode using the Eevee renderer, click the Viewport Shading options drop-down, upper far-right of the 3D View and then the Backface Culling checkbox in Options to enable. All objects in the 3D View immediately display with their backfaces no longer rendered. Click again to disable.
Look Dev + Eevee
In Look Dev render mode using the Eevee engine, Backface Culling is a material property. To enable or disable, select the object for which backfaces are to be culled then in Material properties scroll down to the Settings options and click the Backface Culling checkbox. Surfaces will immediately render single-sided. Click again to disable (render backfaces).
Design note: being a material property means enabling or disabling backface is material specific, it is enabled/disabled per material, and for every instance where they might be assigned.
Rendered + Eevee
In Rendered mode using the Eevee engine, Backface Culling is similarly a material property. To enable/disable select an object with assigned material and in Material properties scroll down to Settings and click the Backface Culling checkbox to enable. The active materials surfaces will render single-sided. Click again to disable (render backfaces).
Solid + Workbench
Switching the render engine to Workbench, and in combination with Solid mode, culling can be found in the Viewport Shading (top-right of the 3D View) under Options; click the Backface Culling checkbox to enable/disable.
Design note: under Workbench an (additional?) option to enable/disable Backface Culling is present in Render properties under Options but is (currently?) non-functional – nothing happens when active. Switching between render engines is done in Render properties.
Rendered + Workbench
Using the Workbench engine and Rendered viewport shading, although the scene is (currently) displayed similar to Solid, Backface Culling is an setting of Render properties under Options; click Backface Culling checkbox to enable/disable.
Design note: with the Workbench render engine active only Solid and Rendered modes are available (Look Dev is not available).
Solid + Cycles
With Cycles render engine set and Solid mode active, Backface Culling can be found in the Viewport Shading menu top-right of the 3D View; under Options, click the Backface Culling checkbox to enable/disable.
Design note: as with other iterations of Solid mode, the feature applies globally when active, all objects in the 3D View appear without backfaces.
Look Dev + Cycles
With the view set to Look Dev rendered using Cycles, the option to enable/disable Backface Culling is (currently) not available so surfaces draw two-sided at all times by default.
Design note: although Cycles defaults to rendering both sides of a mesh some surfaces may render single-sided without their being an apparent way of enabling or disabling this as the option is not provided in Render properties, Material settings or Viewport Shading (but may be included in a later release).
Important: for Cycles rendering and as an alternative, backface culling can be set-up using node based materials. See below for instructions.
Rendered + Cycles
For Rendered viewport using the Cycles engine, Backface Culling is similarly not (currently) available as an option so all surfaces draw two-sided by default.
Design note: it’s important to note that culling backfaces in this context refers largely to Blender providing the option as a selectable setting, something that can toggled on/off with a checkbox. As the effect pertains to surface rendering in a general sense however it is possible to replicate the effect as an appropriately constructed, node-based Material (cf. below).
How to: create a backface culling material that replicates the effect, first create a standard Material – Image Texture » Principled BSDF » Material Output.
To this add a;
– Geometry node – Input » Geometry
– Transparent BSDF Node – Shader » Transparent BSDF
– Mix Shader – Shader » Mix Shader.
Next, link the nodes;
– Backfacing output of Geometry to Fac input of the Mix Shader
– BSDF output of Transparent BSDF to Shader input of Mix Shader
– BSDF output of Principle BSDF to Shader input of Mix Shader
– Shader output of Mix Shader to Surface input of Material Output
If connected correctly object backfaces will disappear (certain elements of the 3D View may not render correctly using this approach – note the grid is missing in the ‘transparent’ areas shown below whilst objects, the green cubes, are rendered without issue). To invert the effect switch the Shader inputs between Principled BSDF and Transparent BSDF.
Using a standard Material as a base, a Geometry and Transparent BSDF node are mixed with the base nodes to create a backface culling Material that reproduces the effect otherwise provided by a toggleable option.
Video: Cycles doesn’t have fully functional Backface Culling but it can be replicated using Nodes.