Our line drawing material detects lines by testing the difference of certain geometric values between neighboring pixels. But because we decide the line for each pixel, the detected lines cannot be thinner than one pixel width. To draw thinner lines, the only way is to provide subpixel information to our line drawing material. In UE4, users can do such a thing by putting higher values than 100 in “Screen Percentage” parameter in the PP volume (Figure 3). We used 200 for our Mixamo demo video scene. Notice the higher value means the higher computation cost for overall rendering. It would be important to minimize the computation cost to find the smallest value of this parameter whe you get the satisfying line quality.
Figure 3. The Screen Percentage option in PP volume to enable thin lines.