Inserting an ebm shape in MGED

Making an image with GIMP

First, we must make an image with GIMP. This image contains the text, or a two dimensional shape that should be loaded into MGED model as ebm.

The image must have a black background and a white foreground.

To get a nice ebm, the new GIMP image should have at least (?) 350 x 350 pixels (width and height).

In GIMP we must change the Image Mode to Indexed Colors with 'Black-white, using the (1 bit) palette' option.

We must save this image in PNG format. In the Save dialog box we must check the 'Save with Background' option.

We must write down somewhere the dimensions in pixels of this image. (e.g., 350x350)

GIMP image of the Y char

The GIMP image

Converting a PNG file into a bitmap file

This can be done with the following command at the shell prompt in an XTERM window on GNU/Linux systems.

$ png-bw image_name.png > image_name.bw
Warning: color image being converted to B/W!!!

We get the warning shown above and this is good. :)

Inserting ebm in MGED

mged> in text1.s ebm image_name.bw 350 350 20

If we don't type the dimensions (in pixels) of the file image_name.png exactly as it was created, the ebm shape that we get will not be good.

the wireframe of the inserted ebm

The Wireframe of the ebm

If we made a region of this ebm and raytraced it, then we can see something like the picture below.

raytraced region of the ebm