Mesh SEO

[Anonymous]

I have spent a few hours trying to model a site plan with paving and curbs. I intended to use a tall concrete wall for my curbs and then use the mesh "paving" raised 6" and SEO subtraction with upwards extrusion to remove the top of the curb wall. This would have given me a 6" curb that would follow the contour of the paving. This did not seem to work. If the mesh is just a surface (no thickness) the SEO dosent work. I then placed a thick slab over the entire site intending to add some thickness to the mesh and perform a downwards extrusion leaving me with a mould to subtract from the walls with, this also did not work. Any one understand what I am trying to do? Mabey the profiler is the proper tool to be using? I just purchased AC so I havent got Archi Terra yet. I know it would help, But unfortunatly I must be done tommorow!? Thank you for all the help guys!

[Anonymous]

Matthew-If posssible could you elaborate on your method of site modeling with 3 copies? Thanks

[Anonymous]

I generally have (or draw) the site plan with the various 2D tools; usually lines and arcs for streets and sidewalks & splines for contours. Sometimes I will work directly with the mesh tool but I usually find it is easier to lay things out with tools that don't have to form a closed polygon.

I then make the basic land form from the outline of the area I want to model and the splines for elevating the contours.

I use the 2D shapes to cut up the various copies of the land form into the different parts of the model. For example, I will cut away all the stuff that is not street from the mesh that is to form the street, and likewise for the land and sidewalks. The cutting is accomplished with a simple space bar click for holes and the pet palette subtraction followed by a space bar click for shapes that cross the edge of the mesh being cut.

The reason for forming the overall land with contours first and working with the copies is that the resulting cut forms will largely match up with one another along the contour lines. I say largely because some nodes inevitably get zeroed out. These are easy to spot and fix in 3D; there is nearly always a corresponding point at the same elevation to adjust them to.

Always check the work in 3D as you go along (the major editing is easiest in plan and the tweaking is best accomplished in the model) since there is always a risk that a mesh will "go hollow" due to some improper boundary condition. One example of this is if you try to bring a mesh node to too sharp a point, such as an edge that is tangent to an adjacent arc. This can happen when you model a driveway separate from the street and wrap it too tightly around the curb cut (better to flow the street into the cut and leave the end of the drive square.

This is difficult to describe any better than this without going into a full blown tutorial. I hope it is helpful.

[Anonymous]

Yes, very helpfull. I think I'm getting the hang of it except I keep getting a message saying "no region found around this point" It seems intermitent. I will keep trying....Thanks

[Anonymous]

Any one have any other tips on how to Cut and modify meshes without causing problems? I have been experimenting with Matthews method. I generated one mesh that covered my entire site. Then I used lines and arcs to layout curbs, landscaping, paving, ect. I used this layout to devise my drainage plan and set my elevations on the mesh accordingly. I then copied the mesh once for each of the site elements (paving, curbs, ect) and saved the original on a hidden layer for backup. I then hid all the site layers except for the curb mesh and the layout lines and arcs. I used these lines and arcs to magic wand into ridges. Some times it seemed safer to just trace the "layout" with the lines and arcs of the mesh tool, I am not shure how to predict the outcome of a trace when there are a bunch of lines and intersections yet. After I had all my curbs traced I started to remove the rest of the mesh piece by piece. I intended to do this with each site element layer and then select the whole layer and raise or lower it an needed. I am having trouble getting good results using the mesh subtraction. I have been watching for self-intersecting edges but still end up with a hollow mesh and other wierd results.

[Anonymous]

You are attempting one of the most challenging modeling tasks there is. I have found that at some level of complexity the mashes start to get quite flaky. On one model involving about twenty city blocks I had to cut the streets up into sections. it seemed that having too many holes for the various blocks was just too much. I ended up cutting the streets so that they had no holes in them (this was where the split command did come in handy). You may find you need to break things up into manageable chunks.