gaps displayed between abutting models when viewed in 3D vertical slices

[Lara]

Hi,

I have a rectangular polygon that is not oriented normal to my coordinate system (i.e. its sides intersect model nodes diagonally).

The polygon represents a backfilled excavation area that I am attempting to model.

I have removed the polygon excavation volume from a larger site model using Solid / Filter / Polygon Clip, replacing interior with null.

I have also generated a model of the backfilled excavation volume by first using Solid / Filter / Polygon Clip to replace the interior of the same polygon with a single unique g-value and then using Solid / Filter / Ranger Filter to replace all other non-unique values (the exterior) to null.

I have I appended these two models in 3D in RW15 and they appear to be seamless from a plan view.

However, when I view a "Compass View" cross section of the combined appended models in 3D by applying vertical slices of the same position to both models simultaneously, I see gaps running between the two models.

Both models are "All Voxels" diagram types and have the same dimensions/resolution.

I would like to see these models abut in 3D section view slices since they represent the walls of a backfilled pit in contact with the fill material.

Any ideas on why I see gaps at the contact between the two models in 3D and how I might fix this?

thanks,

Lara

[Lara]

Here are a plan view and an East view with a N-S slice showing the gaps.

[Molly]

Hi Lara,

The 3D slices appear to be drawn to the node locations, so that there is a gap of one node-spacing between the slices in the separate models.

You'll have better results if you create a new model of the two, combined, and then view/slice it in RockPlot3D. One option is to use the Utilities | Solid | Filters | Replacement Filter, using the interior-clipped model as the host, and the fill model as the donor.

Let me know if you have additional questions.

Molly Mayfield

RockWare Inc

[Lara]

Thanks, Molly.

In my case the interior clipped host model is a p-data model and the fill donor model is a lithology model. Both models have the g-values in the same numeric range representing different things with different legends.

Will RW track the differently sourced g-values in the combined model or do I need to do some g-value manipulation in advance?

Lara

[Lara]

Also, my p-data host model contains null values I need to preserve outside the interior clip excavation area to be filled by the donor lithology model.

[Lara]

Sorry for the multiple replies here. I should probably add that the p-data host model employs a cold-to-hot color ramp while the lithology models uses the lithology table.

(The pictures I uploaded were only tests of the Polygon Clip and Range filter processes I did using simplified test models with only 1 g-value each to demonstrate the gap issue).

thanks,

Lara

[Molly]

Hi Lara,

If the two models need to be displayed using different color schemes, then the replacement filter method won't work because its single output model can use one color scheme only.

If your intention is to display these in cross section in 2D, then you could create them separately and combine the diagrams, as described in this blog post: http://www.rockware.com/blog/rockworks/layering-profiles-and-cross-sections-in-rockworks/ These will not have gaps.

If you need to display the slices in 3D, your other choice is to create separate fence diagrams (which allow diagonal slices) and append them, but these will also show a gap since they use the same 3D display engine as the solid model slices in RockPlot3d.

I'll do a little more research about RockPlot3D's drawing methods - if I come up with any other ideas I'll post them for you.

my best,

Molly Mayfield

RockWare Inc.

[Lara]

Thanks, Molly. That confirms why I have been avoiding the replacement filter and trying to work instead with overlays of the two separate models.

Unfortunately using 2D in RW15 as an alternative for the cross sections requires workarounds involving dummy data (my lithology backfill model only contains one g-value) - please see Tom's response to this recent post of mine:

https://www.rockware.com/forum/index.php?showtopic=2251

I do appreciate you digging around some more on this to find out if there are any alternatives we haven't yet considered.

I'm still not exactly clear on why RW15 3D slices are replacing data nodes with nulls at the filtered edges to create gaps at my contact, particularly when these edge nodes appear OK from the plan view.

thanks,

Lara

[Molly]

Hi Lara,

In the 3D view there aren't nulls - these are just gaps between the node and the edge of the voxel. Remember that a solid model has a regular array of points, or nodes, in 3D space which are assigned the values.

When you view a solid model using All Voxels and set the drawing style to "Voxels" the viewer creates a box or voxel around the nodes so that they are connected. The voxel extends half the node spacing around the node in each direction; picture a box with a point in the middle. By contrast if you set the drawing style to "Points" you'll see the actual locations of the solid model nodes.

It's the whole node-versus-cell thing.

RP3D appears to be drawing vertical panels to the node locations and is not extending them half the distance to the next node. Thus the one-node-width gap.

If you could set your Fill nodes to a value that is outside the P-Data model range, you could create a custom color table which would color the Fill (G=1, say) to brown, and then grade the colors for the P-Data values (G = 5 - 100, for example) using any low-hi color scheme. In this way you could use the combined (replacement filter) model.

Molly Mayfield

RockWare Inc