In Gimp, open the File menu and click - New. Create new image with size 300x300 - black foreground/white background is usually by default. If not set them manually.
Activate the Brush bouton on your toolbox and choose a nice shaped heart
If you don't have heart brushes you can download from many sources - search in google "heart brushes for Gimp" - find, download the zip file, extract and save in your "root/.gimp-version/brushes" folder.
Make a heart on the middle of the white background. Invert the black and white colors - Colors » Invert. This is our pattern.
Type Ctr+d to duplicate the image and Blur this Copy - Filters » Blur-Gaussian Blur and set Blur Radius to about 80
Change your background color to a nice bright red like #ff0000
Duplicate the blurred image then do Edit » Fill with BG Color or type "Ctr+."
Now we work on the red copy. Activate Filters » Lights and Shadow » Lightening Effects. Click Bump Map and Enable bump mapping then for Bumpmap image choose the blurred black and white copy.
Now click Light and change Light 1 to type Directional.
Activate Light 2 set it to Directional.
Then Light 3 also Directional and change the direction a bit to the side.
Click Options and check Create new image and then OK
We have got a nice red Bump and to make it smooth we do Filters - Blur - Gaussian Blur and Blur just a bit 3 or 4.
This is the moment to get our red 3d heart now - Add a Mask to the red Bump image (Layer » Mask » Add Layer Mask and click Add)
Go to the first black and white image and do Edit » Copy Visible (Shift+Ctr+C) and Paste it over the mask layer of the red Bump image (Ctr+V) then Ctr+H to Anchor the layer.
Save the image as .png for better quality
Here is our perfect red heart final product:
3d red heart
Some samples - Valentine's Love Cards decorated with shiny perfect red hearts:
View all Valentine's Love cards