Render layer-filtered SVGs

render_svg turns a DXF layout into an SVG file, filtered to layers matching a pattern. It’s the fastest way to see what a layer inventory or parcel extraction is talking about.

Basic call

{
  "tool": "render_svg",
  "operation": {
    "file_path": "/data/site-plan.dxf",
    "operation": "render",
    "parameters": {
      "layer_pattern": "C-PROP*",
      "output_name": "property-lines",
      "layout": "Model"
    }
  }
}

The file is written to the server’s output directory as property-lines.svg, and the response reports the path, file size, entity count, and SVG element count. output_name must be a bare filename stem — path separators are rejected.

layout accepts "Model" (default) or any paperspace sheet name from list_sheets, so you can render a specific deliverable sheet.

The frozen-layer gotcha

Here’s the trap that motivates this page: DXF renderers normally skip entities on frozen or off layers, faithfully reproducing what a plotter would show. On real civil files, that hides exactly the layers worth looking at — no-plot boundary layers (*-NPLT suffixes) are routinely frozen precisely because they’re working linework, not deliverable graphics.

mcdrafter takes a position: if you name a layer pattern, you mean it. Frozen and off layers that match the pattern are forced visible before rendering. You asked to see the property boundaries; you get the property boundaries, plot flags notwithstanding.

If you want plot-faithful output, render with a broad pattern against a paperspace sheet — the layout’s own viewport conventions carry most of that intent.

Empty results are errors, not empty files

A pattern that matches no layers returns an error that includes similar layer names as a hint:

{
  "error": "No layers match 'C-PORP*'. Similar layers: C-PROP-LINE, C-PROP-BNDY, C-PROP-ESMT"
}

You never get a silently empty SVG to puzzle over.

Block content and layer “0”

Layer filtering applies to top-level entities in the layout. An INSERT (block reference) passes the filter when its own layer matches, and then renders its complete block content — sub-entities inside the block are not individually filtered. This is deliberate: block content drawn on layer 0 legitimately inherits the insert’s layer, and filtering inside blocks would drop valid geometry.

Practical consequence: if a matched layer contains block references, expect their full symbols in the output, not just the fragments that share the layer name.

Performance

Rendering a full sheet of a large civil file (tens of thousands of entities) takes on the order of 10 seconds and can produce multi-megabyte SVGs. Prefer narrow layer patterns — they’re faster, smaller, and more legible. The typical loop is: survey to find a layer, render just that layer, widen only if the picture is missing context.