2.7 - Diagnostics Tools

2.7 - Diagnostics Tools

FormIt comes with some useful built-in model diagnostics tools to help keep your model clean and healthy, including checking for watertight geometry, identifying flipped faces, and viewing all group bounding boxes at once.

In this chapter, we are going to identify and fix some errors built into the Encode Campus Sample Model.axm. If you have not already, you can download the file from the FormIt Primer Part 2 Dataset..

For more information on repairing models, visit the Repairing Solid Models FormIt Blogpost.

Identify Watertight Issues

A watertight model or group is a solid object with no gaps, stray edges, or other non-manifold geometry. Checking for watertightness can be important for calculating volumes, running accurate solar and energy analyses, exporting models to other file formats, and preparing models for 3D-printing or manufacturing.

1 - Once you have opened the Encode Campus Sample Model.axm, we will adjust the layer visibility to isolate the geometry we would like to check for watertightness:

  1. Open the Layers Palette.

  2. Select all layers by single-clicking anywhere inside the list of layers and pressing Ctrl + A.

  3. Single-click on any of the layer checkboxes that is currently on, and all layers will be turned off.

  4. In the Filter input box near the top of the Layers Palette, star typing “Exterior Masonry” until you see just the layer we want.

  5. Click on the checkbox to turn on the Encode Main Building – Exterior Masonry layer.

  6. In the Floating Navigation Bar click on the Zoom All (ZA) button. You should now see just the exterior brick walls of the main building.

2 - Now let’s check for any watertight issues!

  1. Open the Visual Styles Palette.

  2. Select the Model Diagnostics tab (wrench icon) in the top right.

  3. Check the box next to Identify Watertight Issues.

  4. Any watertight issues will be highlighted in Red. In this case there are two, one along the entire top face of the wall, and a small spec which is actually located in a window bay of the building’s rear façade.

  5. Before addressing these issues, select the Exterior Masonry group, open the Properties Palette, note that the Volume property reads 0 cu ft. This is because the group is not watertight, so its volume cannot be calculated.

Note: The red watertight issue highlights are visible through any model material, opaque or transparent, making them easy to find.

3 - Now that we have found watertight issues, we can address them. First we’ll tackle the top face of the wall.

  1. Double-click the Exterior Masonry group to edit it, and then zoom in and select the top face of the wall. In the Properties Palette, note that the top face of the wall is actually its own group. In FormIt, a watertight geometry must be composed of a single group, which is why we are seeing these red lines.

  2. To resolve this issue, simply Ungroup (U) the selected face, and the red line around the top of the brick wall should disappear.

Note: You can also quickly tell that you have selected grouped geometry by the dotted-blue bounding box around the selected geometry. Ungrouped faces and edges will not have this.

4 - Now, let’s handle the other small watertight issue still highlighted in red.

  1. Zoom and rotate the model until you can clearly see the small triangular gap.

  2. While still in group edit mode, use the Line (L) tool to trace a line across one of the longer edges of the triangular hole, then press Esc twice to exit the line tool.

Note: FormIt will automatically create a surface to fill in the triangular gap after drawing a single line. This happens anytime you trace or complete a co-planar group of lines.

5 - The red watertight lines should now have disappeared. To finish up, we will remove the remaining unwanted edge and then re-check the group’s volume:

  1. To delete the unwanted edge, try using the Merge (MG) tool. This tool will join any coplanar surfaces and delete all extra edges in one click. To do this, double-click on the brick wall to select all its surfaces and edges, the right click to bring up the context menu and select Merge (MG).

  2. Press Esc or F to finish and exit the group edit. Then single-click the Exterior Masonry group to select it again, and re-open the Properties Palette, if not already open.

  3. Now that the group is watertight, FormIt can calculate the wall’s Volume for us!

Note: The Identify Watertight Issues, along with examining solids for issues, can also be used to help find any stray edges lying about your model – give it a try!

6 - Don’t forget to turn Identify Watertight Issues off when you’re done, or every stray edge in your model will be highlighted red!

Identify Back Faces

In FormIt when you paint a surface with a material, it is automatically applied to both sides. However, other 3D modeling and visualization software may render a surface differently based on which side is visible; the “front” or the “back”. Luckily, FormIt has an easy way to check this!

1 - Let’s take a look at the existing NE Building. Go to the Scenes Palette, and double-click on the Default Visibility scene to reset the layer visibility.

2 - Instead of using layers this time, double-click on the NE Building group to edit it, and again on its Exterior Masonry group to edit that.

3 - Orbit your view until you can see the front façade of that building, and enable Hide Group Context (H) so you are just looking at the brick walls. Now we can check to see if any back faces are visible:

  1. Open the Visual Styles Palette again.

  2. If not already selected, click on the Model Diagnostics button (wrench icon) in the top right.

  3. If you haven’t already, uncheck the Identify Watertight Issues checkbox, and then activate the Identify Back Faces checkbox instead.

4 - There are (3) back faces that are highlighted with FormIt’s default ‘back face’ color, but due to its similarity to the brick material they are hard to see. To fix this, we can enable Monotone Surfaces:

  1. To display the surface visual styles options, in the Visual Styles Palette click on the Surfaces button (solid cube icon) in the top left.

  2. Check the box next to Monotone Surfaces. Now the back faces are easier to see.

Note: The Back Faces checkbox and color in the Surfaces tab (not to be confused with the Identify Back Faces diagnostics tool), when turned on, allows a user to paint both sides of a face with different materials. Back faces without an assigned material will be colored with whatever color is set in the box just to right of the Back Faces checkbox. This is activated by default when working with imported geometry from software that by default will allow opposite sides of a face to have different materials by default, like SketchUp.

5 - Now all that is left is to flip the ‘back’ faces so we only see front faces. Double-click on the Exterior Masonry group to edit it, and for each of the back faces:

  1. Zoom into and right-click on a back face to brings up the Context Menu.

  2. Select Reverse Face (FF), or type the keyboard shortcut FF.

Note: You can also hold Ctrl of Shift and click on each back face to select them all together, and then flip them all at once by pressing FF.

6 - Don’t forget to turn off both Monotone Surfaces and Identify Back Faces to see the regular materials again.

Show Group Bounding Boxes

This tool allows you to see the bounding boxes of all groups in the model at once, regardless of whether their layer is currently visible or not. This can help you quickly identify groups whose extents are much larger than they need to be, as well as groups with varying axis orientations.

1 - To make all group bounding boxes in the model visible:

  1. Open the Visual Styles Palette.

  2. Select the Model Diagnostics button (wrench icon) in the top right.

  3. Activate the Show Group Bounding Boxes checkbox, and uncheck any others that are still checked.

  4. Zoom out using the mouse scroll wheel or by clicking on the Zoom (Z) tool in the Floating Navigation Toolbar until you can see all the dotted-blue bounding boxes on the canvas.

  5. Even if most of the layers are still turned off, notice that we can see one group bounding box that seems unnecessarily large!

Note: Some of the bounding boxes in this view are at different angles. A group’s bounding box is oriented along that group axis, so a quick way to tell the basic orientation of a group’s internal axis is by looking at its bounding box.

2 - To find out what is making that bounding box so big, let’s turn on all some layers using a pre-made scene and try to fix the issue:

  1. Open the Scenes Palette.

  2. Double-click on the scene named Default Visibility to turn all the main layers back on.

  3. See the vertical line in the far corner of the largest bounding box? Double click on that to edit the group it is inside of, select the line, and delete. Then exit that group.

3 - Now when we look at all the group bounding boxes, there are no bounding boxes that are significantly larger than expected compared to the model geometry.