Missing Glass from Casework Objects in TwinMotion

[genarch]

When using casework objects that have glass doors, the glass panes are not exported to TwinMotion. I suppose it's because there is no thickness to the glass in Archicad. I have UNchecked the option to Optimize Geometry and the option to exclude small objects. I'm using the latest TwinMotion plugin v2.0.2 and TwinMotion 2020.1.

Anyone else have this issue, or have found a workaround?

[genarch]

I’ve now tried this from the latest TwinMotion 2021.1.3 and the latest direct link plug-in v2.0.2, exporting from Archicad v24 4006, and still no glass in casework door panels.

[Emre Senoglu]

i've noticed i have the same problem. so it's definitely not just you.

[Barry Kelly]

I hardly use TwinMotion, so I don't know exactly what I am trying to explain here.
But I recall something about surfaces having a single or double side - I can't remember what the correct terminology is.

I remember with a plant, the leaves looked fine from one side, but when you rotated around they became transparent.
Maybe the same is happening with the glass and you just happen to be viewing it from the wrong side?

I think it is an option you have to make for the individual surface material, not an overall setting.
I may be completely wrong though.


Barry.

[Emre Senoglu]

Hey Barry, just tested this and yep, you're right about the surface normal pointing inwards to the cabinet. Meaning that when you look from the outside, you don't see anything. But when you are 'inside' the cabinet and looking out then you can see the glass pane.

Twinmotion has a setting to make a material 'two sided' and this usually fixes the problem with some other objects (sinks, toilets, showers). However strange enough, it doesn't fix the cabinet issue. The video below will show what I mean - I've made the glass red so it's more noticable. It is quite peculiar.

https://www.loom.com/share/e8662b61856b4d878ff17d37dcee27b7

[genarch]

I often use the glass door panels and make the panel solid instead of glass so I can get cabinet doors with square sticking. Of course, the cabinet door panels disappear regardless of whether they are "glass" or something else. However, if the door panels are defined as glass in Archicad they remain invisible from outside the cabinet even if that material is defined as 2-sided in TwinMotion. However, if the door panel is defined as a solid material in Archicad, it becomes visible when defined as a 2-sided material in TwinMotion.
*Hint, you have to go inside the cabinet to see the panel face from the inside in order to select it and define as 2-sided.

Also, if you export from Archicad as a Sketchup model and import into TwinMotion the cabinet door panels come through just fine... you just don't have that direct link anymore. And if you save that model and try to define it as an existing model for a direct link it won't work, unfortunately.

[Barry Kelly]

I assume it must be because the glass has no thickness.
It is probably scripted as a PLANE rather than a PRISM.
There seems to be no option to add thickness to the glass in the objects.

As a test, make the door frame or cabinet material the same glass and see what that looks like in TwinMotion.

Barry.

[genarch]

It is as expected, or at least as I would expect: the cabinet is glass but the glass door pane is invisible unless you are inside the cabinet. So there appears to be a difference in how that door pane is exported when using Direct Link vs when using a .skp export. This is unfortunate because it makes using TwinMotion a real hassle for residential interiors.

[Emre Senoglu]

This should be an easy fix for GS I hope? Are you able to specify the normal direction (the visible side of the glass pane) when using the PLANE command Barry?

[Barry Kelly]

Emre wrote:
This should be an easy fix for GS I hope? Are you able to specify the normal direction (the visible side of the glass pane) when using the PLANE command Barry?

In Archicad a PLANE is just a PLANE and there is no nomination of what is front or back.
Maybe by the direction in which the co-odinates are specified - clockwise / anti-clockwise?
I am just guessing as I don't know for sure if that would have any affect.

In my objects (not the current Graphisoft default library but they were based on the GS library some 20 years ago), I have the option of 'glass as a plane'.
So I can swap from a single plane surface to a solid prism with thickness.
I don't see that option in the GS cabinets now, but it shouldn't be too hard for them to add that in.
Whether that would ever happen or not though I couldn't say.

I am only assuming that the glass as a plane is actually the problem.

Barry.