Underlay Not Showing All Things

[dgraue]

Boy, this Underlay thing is really confusing me.
I have the level 3 view open and I need to check some alignments from the floor above, so I go to the View Properties and set Underlay to level 4 and set the View Orientation to Plan. Some of the walls and components from level 4 show up, but many don't. I then change the View Orientation to Reflected Ceiling Plan and more walls and components show up...but not all of them. I then change the Model Graphics Style from Hidden Line to Wireframe...now I see all of the walls and components from above (I think) but I now also see the parking stripes from the lower level parking plan. How do I trust that what I see as an Underlay is really from the level I set it too when it is also showing me parking, walls and doors from four levels down?

I checked the View Depth of level 4 and that is set to Associated Level (Level 4). What's going on? I've seen this problem on many projects for years, but it seems very quirky and there does not seem to be any logic as to what shows up (or doesn't) in the underlay.

It's very odd that this hasn't yet been addressed...even in 2009.
Does anyone have a remedy for the rogue Underlay setting?

DG

[dhurtubise]

I believe the cut plane is arbitrary when using underlay

[jeffh]

I believe the cut plane is arbitrary when using underlay

"Arbitrary" might not be exactly right. But it is controled at the system level. The user has no influence on what is shown on an underlay. I think it basically cuts right at the level line and does not really have a "view range" associated with it.

[jtf_8]

Could you reverse that approch and remain on level 4 and underlay level 3 to align, if you notice anything you do not want to see you can hide those elements for less confusion.

I have been doing it this way since they changed the underlay back around 8.1 or so.

[twiceroadsfool]

Worth mentioning-

If an item is such that it shows up in the Active views view range, AND in the underlay Level, it will NOT show in the underlay. For instance:

If im on the roof plan, and i set my Roof Plan View so that the view depth goes down to 3 feet off the Slab: If i have a wall that is 4'-0" off the slab in height, it will not show in the underlay. Consequently, it may not show in my roof plan, if a roof hides it... But it wont show int he underlay because its in the roof plans "view range." If you switch it to wireframe, it obviously shows up.

If you have the same wall, but its only 1 foot tall, you will see it in the underlay, because its not shown in the Roof Plan's "view range."

[dgraue]

Worth mentioning-

If an item is such that it shows up in the Active views view range, AND in the underlay Level, it will NOT show in the underlay. For instance:

If im on the roof plan, and i set my Roof Plan View so that the view depth goes down to 3 feet off the Slab: If i have a wall that is 4'-0" off the slab in height, it will not show in the underlay. Consequently, it may not show in my roof plan, if a roof hides it... But it wont show int he underlay because its in the roof plans "view range." If you switch it to wireframe, it obviously shows up.

If you have the same wall, but its only 1 foot tall, you will see it in the underlay, because its not shown in the Roof Plan's "view range."

That's a good point Aaron and we try to ensure the view depth is set to 0 on associative level for both the main view and the underlay view.

I think we will have to do as JTF suggests and work from above. The underlay seems to be more consistent when viewing lower levels as the underlay. For some reason it gets wacky when the underlay is a level above the active view level.

Since this underlay setting is more for quality control in your workflow and not intended as a presentation display, I would expect that anything showing on the base view should show up in the underlay. It should be much more simple and straight forward in it's functionality...but maybe that's just me. ;)

[dbaldacchino]

There is actually NO CUT PLANE associated with underlays. Take a look at this post

http://forums.augi.com/showthread.php?t=46718

[twiceroadsfool]

See the attached file.

David- Youre right, im not implying that underlays have a "view range" per se, but as was mentioned in the other post, they show the entire contents of the level.

What i was saying in the other thread (which ive attached an example of) is if an element is visible in the ACTIVE VIEWS range, and is also present in the extents of the underlay (in the extents of that level, between it and the level above) it will NOT show in the view range. It will SHOW, because its visible in the view.

BUT, not if something is blocking it, like a roof.

Check out the attached file.

There are 4 walls and a roof. The walls go from L1 to L2.

I made three Floor plans for L2:

NO UNDERLAY, VR NOT DEEP ENOUGH: The view range stops 1" above level 1, and ther eis no underlay, so you do not see the walls (obviously).

UNDERLAY, VR NOT DEEP ENOUGH: The view range of the FP still does not include the walls, so they display in the underlay, as we would like them too (i suspect).

UNDERLAY, VR DEEPER- Now i changed the FP's view range, so it looks down to the bottom of Level 1, which means it is deep enough to see those walls. You still cant see them, because of the roof (unless you put it in wireframe) but they are "included" in the view range. Now, with the underlay on, they are NOT shown in the underlay.

Thats the best i can try to explain it...

[dbaldacchino]

Aaron, your example is a very good illustration of how it works. I wasn't saying you were pointing out anything wrong :) I remember when I was trying to understand underlays that I was getting quite frustrated as I couldn't figure out where the cut plane was, and Support explained it perfectly (there is no cut plane, everything is shown similar to projection although some objects do show up as if they're cut by the level above the underlay level).

The reason objects seem to disappear from underlays where you might expect them to show up is quite logical (well, to some it seems logical, but it takes a while to get there!). If an object is within the view range of the view itself, then it is excluded from the underlay. So if an object is within the view range but hidden by other geometry, the underlay will still not show it because it still is within the view range of the original view. In fact, hiding the roof will reveal that hidden geometry.

[dgraue]

Aaron, your example is a very good illustration of how it works. I wasn't saying you were pointing out anything wrong :) I remember when I was trying to understand underlays that I was getting quite frustrated as I couldn't figure out where the cut plane was, and Support explained it perfectly (there is no cut plane, everything is shown similar to projection although some objects do show up as if they're cut by the level above the underlay level).

The reason objects seem to disappear from underlays where you might expect them to show up is quite logical (well, to some it seems logical, but it takes a while to get there!). If an object is within the view range of the view itself, then it is excluded from the underlay. So if an object is within the view range but hidden by other geometry, the underlay will still not show it because it still is within the view range of the original view. In fact, hiding the roof will reveal that hidden geometry.

There may be logic behind the intent but there are instances that don't follow it. For instance, as a straight forward use of underlay I have Level 4 view open with an underlay of Level 1. The walls and components of Level 1 do not show up as an underlay in Level 4 unless the view is set to wireframe. The walls from Level 1 go to within a foot of Level 2 so they don't enter the plane of the current view. To see if the floor on Level 4 blocked the view of the underlay, I deleted it. No good. I finally determined that it was the floor at Level 2 that was hiding the Level 1 underlay. Once I deleted the floor at Level 2 I could see Level 1 underlay in the Level 4 view set to hidden line.

Level 2 should not have any relation to an underlay of Level 1 in a Level 4 view. Crazy!

[twiceroadsfool]

Can you copy and paste the view range settings for your level 4 view?

[geoffry]

I found this thread because I was having the same problem.

All the posts here helped me understand how underlays work.
There is one issue that wasn't addressed when using underlays: Ceilings and Floors.

After trying many of the suggestions from this thread, I soon realized that I could see everything on the udnerlay that wasn't covered by a floor (in R.C. Plan view) and ceilings (in plan view).

Maybe this is the same issue some others are having.

I hope this helps.