Here is a link to an article I wrote for AECbytes.

• Quote:

Gayla -

Sometimes it is easier to select elements while in plan, so feel free to switch back and forth between 2d and 3d views. You can use the SEO palette to do the subtraction while selecting things in plan or section, it works the same as when you are in 3d although you may not see the result until you go back to 3d.

Another possiblity is that you may be having an issue with layers – if you activate a "normal" 3D view there is one SEO layer that is usually turned off – the one that is intended to be invisible in a 3D model since it contains elements that are created purely for "cutting purposes". You may have to manually turn layers on to see the driveway, depending on what layer you placed it on.

Sometimes I will stay in 3D but use the View menu > 3D Window Settings > Wireframe to be able to see "through" elements. This can be visually confusing, since you may have a lot of lines, but if you set your view properly it may be helpful. Remember when two elements share the same node, edge or surface, if the arrow tool prefers selecting one of them while you want to select a different one, you can use the Tab key on your keyboard to cycle through the preselections (each element should be highlighted in turn), and when it highlights the one you want, then you can click the arrow tool to select that one.

I hope this helps you figure it out – let me know!

Eric

Gayla -

It is possible you actually made the slab disappear in 3D because you did a subtraction instead of an intersection. You can start over with the SEO operations by using the lower section of the SEO palette – I think it's called Maintain SEO or something similar – and select one of the options to cancel the SEO. The simplest way is to select the slab in plan (where you can still see and select it) and use the palette option to cancel SEO on operators (related to the current selection). This will allow that slab to be seen in 3D starting fresh, since it will not be affected by any previous SEO operations.

Then, make sure to do the operations in the proper order: select the slab, make it a target, deselect the slab, select the mesh, make it the operator, then do an Intersection; then select the mesh, make it the target, deselect the mesh, select the slab, make it the operator, and do a Subtraction.

Let me know if this helps you to get this working properly!

Eric

Gayla -

As I recall, we resolved this issue in the Best Practices Course coaching call on February 2. I think it might have been caused by your use of the mesh tool with the option that makes it not solid, just a covering skin. At some point I'll review that coaching call and post the resolution here to close this discussion. If you get a chance to return here, feel free to share what we figured out.

Eric