I asked GRAPHISOFT about this and I got the following response:
1. Although it is possible in IFC4 to save texture information (the specification contains it), there are no currently available Model View Definitions - MVDs - (such as Design Transfer View and Reference View) in which textures are specified or supported. Neither of these MVDs has it as a purpose to visualize textures. Thus the first step would be to demand such a MVD by users/organizations/standards.
2. Also, texture support in IFC4 currently exists only for triangulated geometry. For BREPs there is no support because it is very complicated.
3. There is no IFC-supporting application currently (including IFC model viewers) which would have even started developing/supporting texture import/export.
4. GRAPHISOFT worked very hard to get color fidelity of surfaces implemented in IFC. (that is, in an IFC file exported as BREP from ARCHICAD 20 each face of an object can have a different color, as opposed to earlier where each surface of a body had to have the same color). Besides GRAPHISOFT, only a handful of application have implemented this enhancement. So imagine, if there is such low support for color fidelity at the moment, how much support is there for texture fidelity?
Based on all the above it seems to me there will be some time before we see textures in IFC files.
Loving Archicad since 1995 - Find Archicad Tips at x.com/laszlonagy
AMD Ryzen9 5900X CPU, 64 GB RAM 3600 MHz, Nvidia GTX 1060 6GB, 500 GB NVMe SSD
2x28" (2560x1440), Windows 10 PRO ENG, Ac20-Ac28