BIM_SUBTRACT unexpected behaviour

Daniele Piazza

I'm just attemping to use BIM object to create mechanical features (holes). I created a bim-hole sample containing just the 3D solid on the BIM_SUBCTRACT layer. The model works fine but when the hole extend over the containing solid I can see a protrusion on the opposite side. Using a 3D subtraction this should not happen.
Do I miss something.

Daniele

Attached you have the sample to test.

Roy Klein Gebbinck

I have not yet looked at your files, but my first guess is that you have not switch off the BIM_SUBTRACT layer.

Jason Bourhill

I've played around with this idea previously and struck similar issues. For me it works ok until you try and create a thru hole. At this point I get a protrusion on the solid equal to the hole diam, per your example. Also find that the parametric nature of the hole stops working, adjusting the hole parameters no longer works. This was with V15, haven't attempted with V16.

Could be very useful if it worked consistently! Of course you could say this is taken out of context to the original intent of the command, but I think there are valid examples in an Architectural context, such as a circular opening (Oculus) in a domed roof.

Regards, Jason Bourhill CAD Concepts 

Roy Klein Gebbinck

The problem seems to occur if the hole initially created by the _BIMINSERT command is not through and through. You can fix it by using the _BIMWINDOWUPDATE command.

Roy Klein Gebbinck

... And the problem of 'misbehaving' parametrics can be solved by reloading the file:
Properties Bar > Parameters > File > [...] > Select the orignal file.

Jason Bourhill

Here is my example. I re-modelled in V16. The hole diameters and depths are driven by parameters, which perversely requires the Mechanical Browser to be open to modify. As Roy noted you need to use _BIMWINDOWUPDATE to see changes. Seems to work!!

Regards, Jason Bourhill CAD Concepts 

BasePlate(2).dwg

BasePlate.png

Daniele Piazza

 OK! I left the layer visible on purpose to show something in the sample. Anyway the BIMWINDOWUPDATE works as expected.

I would recommend the Bricsys guys to remove the *WINDOW* term in the command.

This pattern has great potential, not limited to BIM only.

I hope that when the BIM spin-off will leave the BricsCAD core (maybe next year?) this feature remains available.