Hi all,
Knowing that the OSM simulation (for example for calculating surface temperature) has a limitation that I have noticed
It cannot calculate a surface that has a small area (probably below 0.01 sqm)
I was wondering if there is a workaround for this?
For example, you can see in this simulation that a small surface like the one in blue is not included in the calculation
Hope somebody or @chris has a solution for this
Thank you 
Regards,
Ricardo
Try to use a smaller model tolerance. Note that this would introduce more issues that didn’t exist before, such as non-planar surface issues.
If it doesn’t help, then you will need to merge those surfaces or find a way to create larger surfaces.
Hi @ricardo ,
1 centimeter is the absolute tolerance that is built into EnergyPlus and this cannot be changed. Any geometry that is smaller than this will be ignored in the E+ calculation, though (like Mingbo says) we still support you making geometries like this in Honeybee if you lower the Model tolerance since they can sometimes be useful in Radiance simulations if you set your radiance parameters correctly.
Even if this E+ absolute tolerance could be changed, the result you’d get would not be very accurate because, at a scale that small, the surface area is likely smaller than the construction thickness, making it inappropriate for the 1D heat flow assumptions of E+ (or any BEM software for that matter).
Why do you need to model a Face that small?
Hi @chris ,
Thank you for getting back to me
I wanted to model part of the facade panel, which, unfortunately, has a small component like that.
I am guessing E+ not including several small parts would affect that particular facade’s overall average surface temperature.
I understand that BEM is mostly used to calculate an overall building surface, not a small, detailed, component like this.
I am thinking of using Finite Element instead of BEM software, but I was just wondering if Ladybug itself is capable of doing so.
Thanks for the explanation, @ricardo .
If you’re modeling heat flow through components that small, then you are correct that 2D or 3D finite element heat flow solvers are the much better simulation tool to use rather than BEM software, which pretty much universally uses 1D heat flow assumptions.
Legacy Honeybee had a connection to the THERM 2D heat flow solver, which you can use if you really need this capability in Grasshopper. Hopefully, we port something like this over the LBT at some point but you would have to use Legacy Honeybee for that for now.
