Good afternoon. Can anyone recommend the best method of modeling topography from a PDF?
Thank you.
“A PDF” isn’t much of a description of what you’ve got. Is it raster-based or vector-based? How does it portray elevation data? Does it show contour lines? Spot elevations? Something else?
-Gully
Hey Gully,
I don’t really know if it’s vector or raster based. Not sure what the difference is?
The survey shows contour lines at 2ft increments vertically.
Thanks
-Chris
add the file and someone can advise…
john
You can import the PDF, trace the lines, then offset them vertically to create your lines. Then you can use Sandbox to create a from the lines.
A pdf file can be a container for either raster or vector graphics.
Raster graphics are like a bitmap, say, jpg or png or gif. They portray graphic information by showing a grid of pixels, which may be on or off, or red or green, and so forth. It takes some kind of intelligence, either human or software, to interprt the grid of pixels into a picture.
Vector graphics store picture elements as actual lines or arcs or circles, with each of the primitives stored as mathematical expressions. A line knows it’s a line and where it is and how long it is.
The practical upshot is that you are going to build your topography out of the contour lines on your drawing. If it’s a raster image, you’re going to have to import the image, trace the contour lines, raise each one to its designated elevation, and then run From Contours to generate the terrain. If it’s a vector-based drawing, you can skip the step of tracing the contours, because they are already line entities that SU can manipulate.
The other issue is importing the pdf. If you’re on a Mac, pdf support is built into the OS. If you use Windows, you need to use an import filter.
-Gully
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When viewing a PDF file in a PDF viewer, if you can zoom in as much as you like and the edges of lines remain sharp and crisp instead of breaking into pixels, you are probably viewing a vector-based file.
A vector PDF can be converted into a DWG or DXF file in Illustrator, Corel Draw or Inkscape and imported into SketchUp Pro, or into Sketchup Make with a DXF-import plugin. That might spare you from redrawing the contour lines.
Anssi
Thanks so much for the replies and explanations. Very helpful. Looks like I have a vector based PDF
I was able to get the .dwg file. Viewing from a 3d View, it seems that it was drawn 3dimensionally. Autocad Civil??
How would use/convert this in Sketchup. I’m assuming this is easier to use than the PDF.
Thanks again,
-Chris