Material property IsTwoSided not work

[renanfaccin]

When I export a WPF 3D model to GLB format, and to open it later in a viewer like Babylon.JS/glTF Viewer some sides are hidden it when rotate camera. The Assimp library (AssimpNet) has a property for enable double side, IsTwoSided property, however, is not work when I set true value.

Code snippet: ‌

Follows the evidence of the problem:

Original model ‌

Model opened in Babylon.JS viewer ‌

Would appreciate if you can help me.

[andersonnichele]

I have the same problem. When you set IsTwoSided as true, AssimpNet calls the code above:

            set
            {
                MaterialProperty prop = GetProperty(AiMatKeys.TWOSIDED);

                if(prop == null)
                {
                    prop = new MaterialProperty(AiMatKeys.TWOSIDED_BASE, value);
                    AddProperty(prop);
                }

                prop.SetBooleanValue(value);
            }

The value of AiMatKeys.TWOSIDED_BASE is "$mat.twosided".

A glTF/GLB material with value twosided as true should define the backside color.

[swx2k]

export of doubleSided does not work since the exporter uses a boolean variable instead of an integer. Since there is no handling of boolean property values it is treated as a buffer instead which causes the Get function to fail. A simple workaround could be to do: int doubleSided = 0; mat->Get(AI_MATKEY_TWOSIDED, doubleSided); m->doubleSided = doubleSided != 0;