Transparency / Blender

Here we show how to enable transparency for Eevee/Cycles and glTF-compliant materials in Blender.

For usage example, check out the following demo from the Asset Store: Transparency.

Blended vs Masked

Being a real-time 3D engine, Verge3D offers two main methods to handle transparent objects: alpha blending and alpha clipping (usually with an image mask). Blending enables combining a translucent foreground color with a background color, using the foreground color's alpha as blending factor. Clipping, on the other hand, simply discards all pixels with alpha less than some predefined threshold (by default 0, but can be changed in material settings).

Blender Alpha Blend vs Alpha Clip comparison

Blending enables for smooth transitions, generally looks nicer but computationally more expensive than clipping. It may also produce z-sorting artifacts when polygons appear to be rendered in wrong order. Clipping works best for visualizing numerous small objects (such as grass or tree leaves). It also produces hard edges without any transitions which may be aliased.

Additive Composing (aka No Depth Writes)

Verge3D also offers a special mode for disabling writing to the depth buffer while rendering. This results in polygons being excluded from pixel depth comparison. Such polygons are composited in additive manner, which sometimes can help get rid of blending artifacts.

Rendering with no depth write

To enable this mode, disable the Depth Write option located on the Verge3D Settings panel.

Depth write setting in Blender

Rendering Order (aka Z-index)

Verge3D does not perform sorting of polygons inside objects, but rather performs sorting between objects. This provides correct blending in most cases but sometimes one may need to forcibly change the rendering order for an object.

To modify the rendering order for a particular object, change the numeric field in the Verge3D settings panel. The smaller the index, the earlier the object will be rendered.

Render order setting

So, if you have a transparent, continuous object in the rear and want other transparent objects in the front to render correctly, set some negative value as the rendering order of the rear object.

Rendering order example

Transparency for Eevee Materials

Transparency for Eevee materials can be enabled by using a combination of the Transparent BSDF and the Mix Shader nodes. The factor in the Mix Shader node can be used to define the alpha value - you can directly specify a value or create a dependency from some other nodes such as Fresnel for more realistic look.

Blender Blend mode setting

Use the Blend Mode dropdown to choose between transparency modes.

Alternatively, you can use Alpha input of the Principled BSDF node.

Principled BSDF shader with transparency

To tweak your the material's transparency there are other options available on the Settings panel:

Transparency for glTF-compliant Materials

In order to enable transparency for such materials, add alpha mask information to the alpha channel of the base color texture. Also you can tweak the alpha channel with the Alpha input of the Principled BSDF node.

Transparent glTF material

Use the Blend Mode dropdown to choose between transparency modes.

Got Questions?

Feel free to ask on the forums!