Splitting Topo Surface Sucks

[sjsl]

I love this program and have already forgotten half of what I knew about Acad, but I am truly frustrated w/ topo surfaces. Maybe someone can add their two cents.

I am trying to split my topo into sidewalks. All goes well when tracing/picking over my acad underlay. What happens when I try to finish sketch I get the error message
You have to split tpo surfaces exactly. It highlights the entire line pattern. Great but it does not do me any good because it does not identify what surface is at fault.

We need alot better error trapping on this issue. I have to go back and keep tweaking 40 line segments to get this feature to work.

I believe I will just use the floor tool.

Any ideas?

[christopher.zoog51272]

It all boils down to how good your underlying acad drawing is, if there are tiny gaps in the lines or fillet problems, they will come through in revit. When I encounter such issues I got back to acad to clean up the linework, or just draw my own "chain of lines"


I agree about the error trapping, I wish the loose endz would get higlighted like thy do during floor errors.

[Tom Dorner]

When splitting topo surfaces they need to be split into exactly two pieces. For more complex splitting it may mean dividing the surface splits into more areas than you want in the final.

Once split, you can then join areas if you need to to bring them back together.

Tom

[Steve_Stafford]

Accepting that you are "stuck" for now...a couple tips (you may already know...) I'm tempted to change your title to something less "yucky"...but then it won't sound as frustrated? :smile:

You have to make sure your cut path divides the surface into exactly two halves. This is the issue I see folks have most of the time. Unless a sidewalk is really an "island" in a site plan you can't always cut out a sidewalk in one operation.

In case you don't know already, hovering over a line and pressing tab will highlight all the lines that are connected end to end. This will give you hint what is causing the problem.

If you finish a sketch earlier, as you go, using simpler lines to cut the site you can test your progress. One UNDO will put you back in sketch mode and let you continue to refine your cut path and you'll get farther along and catch your errors earlier too.

As an example, a curvy path might start as one straight line cut, FINISH, it works, UNDO, sketch the first series of curves, FINISH, still works, UNDO, continue till done....(plus you could leave for a meeting or lunch and come back as long as the same session is running)

Last, even though Revit topography isn't a solid (would be nice if it were), if you think like clay modeling, start with more than you need and carve away what you don't want. A little bit at a time.

[sjsl]

Yeah, I have looked at various ways to split. I have done exactly what you have suggested, it is an OK workaround. I have decided to look at the splits in a different light but have not tried this yet.

Instead of working with the sidewalks and plitting them out of the topo, I am thinking it may be better to split the lawn areas out of the topo. It may reduce the potential number of join problems. I am also going to look at the constrcution of the acad files more closely for their own join problems.

Wouldn't it be nice to be able to just have Revit look at your dwg and tell you where the line connection problems are.

I have also instructed my trainees to just draw their own splits rather than relie on bad base info for now.

Thanks for the input.

Yes, perhaps sucks is a bit more unpleasant, yucky works as well.

[Chad Smith]

Yes, perhaps sucks is a bit more unpleasant, yucky works as well.
Nope, I think SUCKS is a perfect description of topography objects.

Here are my comments about topography objects.
http://forums.augi.com/showthread.php?t=2530&highlight=topography

[Steve_Stafford]

...is a perfect description of topography objects....Perhaps you'd be happier with ADT's topography options? :razz:

"just pick'n on ya"

[aggockel50321]

Another method that I find helpful, is to go to settings and create a new line style subcategory called say, "topo edges". I usually make it a bright color, so it's easy to discern from all the other clutter.


Using this line style, I then use the line tool to lay out all my splits over the topo, whether by picking off an underlaid .dwg or by sketching. I also try to make sure the lines start at topo edges or extend past the edges. As Steve mentioned above, once the lines are placed, it's easy to double tab on a line segment to see what's included in the chain, & fix any breaks.


I then invoke the split surface command, & using the pick option, double tab over a topo edge line segment to get the chain, & then finish the split.


I find the advantage to this is if I screw up two adjacent surfaces, it's easy to merge them & start over.


The other advantage is if I have to dimension the topo edges to lay out a driveway or path, for instance, I can dimension linearly (sp?) & radially to the topo edge lines easily. Revit won't dimension (as far as I can figure out) to topo edges.


Then, if I don't want the lines in a final view, I just turn them off in view/vis. or change their color & line weight to mask them into the surface.

[Wes Macaulay]

Perhaps you'd be happier with ADT's topography options? :razz:

"just pick'n on ya"Woohoo! Drape-type mass objects!

[sbrown]

After many hours of creating topos in revit I have come to this conclusion, it is far easier to create many small pieces, then merge the surfaces, instead of trying to do entire roads/ sidewalks in one path. Much less painful.

So just take your whole topo and split it piece by piece tracing over your autocad drawing, don't even use pick just trace with chain and you will be less likely to have "holes".