How to Use a Digitising Tablet in BricsCAD

Quick answer: A digitising tablet lets you trace paper drawings into a BricsCAD drawing, or launch commands directly from a printed tablet overlay. TABLET configures, calibrates, and toggles tablet mode, and requires Wintab32.dll (from Wacom Technology) installed in C:\Windows\System32.

Setting Up a Digitising Tablet

1. Install the appropriate driver for your tablet.
2. Confirm Wintab32.dll is present in C:\Windows\System32.
3. Download the tablet overlay and CUI files.
4. Print the BricsCAD tablet overlay.
5. Load the overlay CUI file.
6. Start BricsCAD and initialize the tablet.
7. Configure it, part of the tablet surface becomes the menu area, another part becomes the screen pointing area.
8. Calibrate it, enabling you to trace geometry from a paper drawing or image into a BricsCAD drawing.

Downloading the Tablet Overlay and CUI Files

Octave provides a Tablet.zip file for download from bricsys.com’s tools section, containing: overlay.png (the overlay image), overlay(A3).pdf (for printing on A3 paper), overlay(cm).dwg and overlay(inch).dwg (each with the overlay image attached, and two layouts for printing in decimal or imperial units respectively), tablet.cui (a partial CUI file for tablet use), and tablet(acadLike).cui (an AutoCAD-like partial CUI alternative).

Loading the Overlay CUI File

1. Extract the overlay CUI files to the Support folder of the Roamable Root folder, the same location covered on this hub’s user files page.
2. Load Tablet.cui as a partial CUI, the same mechanic covered on this hub’s CUI loading page. It loads automatically on future BricsCAD startups.

Make sure overlay.png extracts to the same folder as the DWG files, and repeat this procedure if needed after a BricsCAD upgrade.

Switching the Tablet On or Off

Click the TABLET field in the Status Bar, press F4, or run TABLET.

Configuring the Tablet

1. Launch TABLET and choose Configure.
2. You’re asked whether to align the tablet overlay; type Y or choose Yes.
3. You’re prompted to digitize the overlay’s upper left corner; click that mark.
4. You’re prompted for the lower left corner; click that mark.
5. You’re prompted for the lower right corner; click that mark.
6. You’re prompted for the lower left corner of the screen pointing area; click that mark.
7. You’re prompted for the upper right corner of the screen pointing area; click that mark.

The command reports “Tablet configured” once finished.

Calibrating the Tablet

Calibration needs at least two points; more points improve accuracy, especially useful for non-orthogonal images like aerial photographs.

1. Launch TABLET and choose Calibrate.
2. You’re prompted to digitize point #1; click a point on the tablet.
3. You’re prompted for that point’s coordinates; either click a point in the BricsCAD drawing window, or type the X,Y coordinates directly.
4. Repeat for additional points, up to 10 total, or press Enter to finish.

The response depends on how many points you specified: with exactly 2, BricsCAD reports “Tablet calibrated” directly (an orthogonal transformation applies automatically). With 3, or more than 4, you’re asked to choose between Orthogonal and Affine. With exactly 4, all three options are available: Orthogonal, Affine, and Projective.

Transformation determines how tablet points map to screen points:

• Orthogonal: best for accurate paper drawings, preserving all angles and relative distances.
• Affine: preserves parallel lines, but not necessarily the angles between intersecting lines.
• Projective: preserves neither parallel lines nor angles.

Frequently Asked Questions

What software do I need installed before using a digitizing tablet with BricsCAD? Wintab32.dll from Wacom Technology, placed in C:\Windows\System32, alongside your tablet’s own driver.

Does the tablet overlay CUI file load automatically every time I start BricsCAD? Yes, once loaded as a partial CUI, it loads automatically on every subsequent startup.

How many calibration points can I specify? Up to 10, though a minimum of 2 is required.

Which transformation type should I use for tracing an aerial photograph? Additional calibration points are particularly recommended for non-orthogonal images like aerial photographs; with exactly 4 points specified, Projective becomes available alongside Orthogonal and Affine.