Geological model volumes not snapping to borehole data

JamesBlack

I am producing a geological model using borehole data, however some of the units will not snap to the data even though 'snap to data' is selected. Is there any workaround to this issue?

DavidWatkins

Hi JamesBlack,

Snapping to data allows the mesh to be modified locally to snap the mesh triangles to the selected data, but only as long as the data falls within the maximum snap distance, which if set to 100% is equal to the GM surface resolution.

I would suggest trying:
- Max snap distance at 100%.
- If modelling with more than just drillhole / borehole data, then select snap to drillholes / boreholes only to ensure that there aren't multiple datasets which may be conflicting, pulling the surface in different directions.
- Increase GM surface resolution so that the mesh triangle size and maximum snap distance is increased, but enable adaptive resolution to retain your detailed mesh resolution around your data.

See the help topic below for addiotnal information on surface honouring:
https://help.seequent.com/Geo/2021.1/en-GB/Content/concepts/surfaces.htm?Highlight=honouring surface



You may need to experiment a bit to get the results you are looking for, but I hope that helps point you in the right direction.

Regards,
David

CharlesLogan

How is the actual distance in 'snap distance' measured?  From the given point to where?  In other words, how does LF determine if a point exceeds the snap distance or not?

DavidWatkins

Hi @CharlesLogan,

The maximum snap distance if set to 100% is equal to the resolution that that GM has been set to, so for example a GM resolution of 5 m would result in a maximum snap distance of 5 m. Then if a GM surface is set to snap to certain data, e.g. on drillholes, if the drillhole contact / data point is within 5 m in 3D space of where the surface was originally, then the surface triangles will be locally moved or added to accommodate the snapping of the surface to the selected data point.

I hope that makes sense.

Cheers,
David 

JamesLally

so what happens when the mesh resolution is set to adaptive? does the maximum snap distance refer to the 'parent' triangle size?

DavidWatkins

That is correct @JamesLally!

JamesLally

thanks @DavidWatkins. I think this explains why I have had similar problems with snapping on models that I'm using adaptive mesh resolution to cover areas that include sparse and more dense drilling. It would be nice to have more localised control over mesh resolution that still enabled snapping in dense data areas. 

KarenFu

So does this mean, lower the resolution the shorter snapping distance? So if I need a high resolution mesh but the data point varies greatly within a short distance (more than the resolution say 5m), data point would not be snapped?