DWG vs. DXF: what to check in drawing files before a quantity takeoff

How DWG and DXF differ

DWG is the native format in which CAD programs save their work. DXF is an interchange format available in ASCII (text) and binary forms. Both can store lines, circles, text, blocks and layers, but exporting to DXF can simplify or omit information.

• Block (bundle of symbols): Depending on the export settings, a symbol stored as one DWG block may become separate lines in DXF. Once exploded, it can no longer be counted by block name.
• External reference (Xref): An electrical drawing that references an architectural plan may open with device symbols but no walls if the referenced file is missing.
• Fonts and text: Missing Korean font files can make legend text unreadable even when device symbols still display correctly.

Five checks when opening a drawing

1. Sheet organization: Check whether floors are drawn side by side in model space or separated into layout tabs. Use this structure to define the takeoff area.
2. Layer status: Devices on hidden or frozen layers may not appear. Check layer visibility, freezing and takeoff scope. Locking a layer restricts editing; it does not by itself hide devices.
3. Block preservation: Click the symbol. If the whole object is selected, it is a block; if only one line is selected, it has been exploded.
4. Scale and units: Different drawing units or scales across sheets can cause errors when using distance to identify duplicates.
5. Revision marks: Record the revision number and date in the title field along with the file name. For more information Drawing revision controlPlease refer to .

What to request with the drawing files

Request the following information with takeoff drawings to reduce the need for follow-up requests.

• Original DWG, saved version and, if possible, a DXF copy
• External-reference and font files, or a copy with the references bound into it
• Legend and general-notes sheets
• Dwelling-unit type schedule showing which plan applies to each building and unit
• Current drawing revision index

How Voltix handles drawing files

Voltix accepts DWG/DXF files up to 50MB per file. Submitted drawings are used only for the takeoff and are not shared with other companies. Provide the buildings, floors, dwelling units and legend sheet to help establish the scope. We may ask for additional materials if blocks are exploded or references are missing.