Help with creating faces on an imported CAD file...
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I already used drape to project the drawing on a face, to assure all the edges were coplanar. I already used Stray Lines plugin. No use.
Dont really know what to do.
as you can see, I have a street and a sidewalk. I want to separate both with different materials... but they are the same face! I retraced all the edges of the sidewalk, to separate it from the street... no luck. If I draw a rectangle, completely inside the sidewalk, it will create another face. But as you can see in the image below, if I draw the rectangle across the sidewalk, it creates a face on the left (inside the street) and a face on the right. But the middle part (the sidewalk) still wont be separated from the rest of the model! What kind of evil sorcery is that?
I will upload the model as an attachment... its a big model... I had projected the whole avenue onto a giant face, but there were similar problems all over the avenue. So I tried creating several different faces objects and project one part of the avenue in each face, to make the cleanup easier, but it didnt help.
So, I need to understand why this thing is happening, and how to solve such problem, after all, I am showing only a single of multiple similar problems along a huge model... so I need to solve all of them.
Thanks
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This often happens with these imported and draped objects. The reason is sometimes rather mysterious. You can try to divide those offending faces into triangles first to identify a problem if there is any or if there is not, eventually get to your faces. When dividing, one part will (hopefully) get separated then go on the part which is still obnoxious.
Turning on profiles (and maybe endpoints) can also help identifying edges that do not want to merge.
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Just a quick check I note that your primitive geometry is not drawn on layer zero. SU uses layers for visibility control( layers) only via components. Don't know if this is your problem but check is in order
Once I move them back to layer zero I used thoThoms selections toys and moused over some that are not forming and they do not show closed loop so may want to check that also. -
You can try the different plugins such as Makefaces.rb or the different "flatten" scripts. Look in the plugins index for those that try to work with imports, flatten vertices, or make faces. Also some plugins try to close gaps. Some might work better for your situation, but making faces with imported geometry is often problematic, even when the spaces are really closed with edges. You can sometimes stitch it down until it is tiny triangles and it will work but that's so laborious.
Note that the way circles and arcs are imported, some lines may actually not intersect on the resulting polygons. -
@pbacot said:
You can try the different plugins such as Makefaces.rb or Flatten.rb.
those were not of much use to tell the truth.
intersecting the selection with itself has helped in some cases.
where it fails, I check for stray lines (with the plugin). Where it fails, I do the labor intensive triangulation method and retrace lines, specially on curves. It sucks. But it usually works, even though there are apparently no gaps (if there were, Stray Lines would find something)
Has anyone ever tried SMustard´s IntersectOverlaps plugin? It seems to do exactly this work
http://www.smustard.com/script/IntersectOverlaps@unknownuser said:
IntersectOverlaps is a great script for "fixing" an imported CAD drawing.
Symptoms that you might have overlapping and non-intersecting lines is that faces will not create where you want them to be created, or if they do create, they cross lines in your model. Faces are not supposed to do this.
Overlapping and non-interecting lines in SketchUp are fairly easy to spot, once you know what you are looking for.
A series of examples follow. The first image shows a rectangle with properly drawn lines inside the rectangle. The inner lines, we can see, are lighter in weight (thinner) than the darker, heavier, bounding lines. You can also observe that there are four distinct faces by activating the pushpull tool and hovering over each of the faces. None of the faces cross a line.
unforunatelly, this is not the best moment financially speaking for me to buy the plugin (and to worse it all, the Real to Dollar conversion rate is in its worse in several years to buy stuff in dollars)
but even if I decide to buy it later, I would need to know if it WORKS for these situations, before spending the cash...
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IF you do what I suggested you will be ok. You can then run the strayline plugin which is free and get the idea of problem areas and fix. I found 145 problem areas in a quick check and they were repairable. CAD files are notorious for this type of problem. The problem of fixing these types of problems with plugins is they usually assume some type of spacing error and don't always fit you case. Plus if it is an spherical error then geo can changes. I tried ThomThoms clean up and but it was deleting geo that should stay. He also has what is called plan tool but have not used so don't know if that will help.
You just need to hang in there. It will take a little work.
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what exactly do you mean with "primitive geometry", that I should move to layer 0??
anyway, aside from the errors that strayline finds, there are some lines that are crossing, on the same plane, but they dont intersect (not in the Sketchup way, in which if you intersect a line with the other, they "weld" and cut each other too...
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lines, circles etc.
To do that open up the layers drop down, select the three below layer 0 and at top select the minus sign. You will then be given three options and elect the one to move contents to default layer. If yo now go back and double click one of those components( group) to get in edit mode, then select say a line and then look at the entity drop down you will see it is on layer0. You can then go back to the layer drop down and make a new layer, select that group ( don't double click ) you can re-assign that group to that layer but its internal geometry will still be on layer zero where you want it. I would recommend you use components but not necessary. You can recreate the other two layers and gives you the capability of hiding geo while you model and the others not interacting with each other.
BTW when you use the staryline tool make sure you are in the context of the group( double click first). Also to correct some errors ( like you may have a case where two lines do not quite meet at the vertex in maybe easier to use the move tool to grab the end point and move to the other one. However that can distort geometry so I will often delete one of those lines and move the others end point to the terminus connect vertex of the deleted line. The use of the triangle approach is useful soem times but you should not need it much.
Also if you go to windows preference, extensions, utilities and make sure extensions are enabled then on the tools tool bar fly out it will have a create face option under utilities. That sometimes is helpful because it will say why a face was not created. It is not very robust however.
Hope this helps. You will learn some of these moves as you model more. Its a learning experience
SU implemented an auto intersect in I think was 7 so crossing planar lines in the same context will do what you describe. It is normal. If they are in two different components they will not do that.
good Luck
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