Hi,
I think this is a bug rather than a corrupt file. I think this happened at the last update. I have an old design with a file date of 28/1/2016, lets call this file-1. After an update when I opened this file SH3D said it was corrupt, it fixed it, and then I saved this as file-2. File-2 has date 13/2/2016. I can now open file-1 (which still has the 28/1/2016). Backup is also 28/1/2016. I don't know when the issue happened but both file-a and file-2 have it.
What has happened is the frame of the windows have disappeared, but not all windows. The glass is there but the frame is invisible. I see that invisible is now a new option, I had these windows set to colour so I think a model translation has failed to account for the extra option inserted which is why colour changed to invisible.
I can go in and edit the model and change the frame of the window back to colour and the frame appears. I can change the colour ok. The reason for me setting colour was to make the window frames look white rather than grey, But now setting colour to white (RAL9010) it still looks grey. The reason for this is that if I select white (#FFFFFF) this doesn't stick and when I next edit the model the setting for the frame material is the unchanged option, not colour. I have to set colour and #FEFEFE to get it to stick.
Please provide a simplified example showing the problem because I couldn't reproduce it.
About choosing a color, if you select a color that is the same default color, it will remain as unchanged. Choosing a white color may not render as full white because of shades rendering.
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