# how to define stimulus through vtx file in 22_simple experiment

Hi,

I tried to use .vtx file defining stimulus points for 22_simple code, but met the error below:



L5 : error: Empty stimulus[0] electrode def! Aborting!



Could you provide some suggestions about this? Thank you so much!

To reproduce the experiment, the modification would be:

1. create stim.vtx, where points 0, 1, 21, 126 are left bottom corner mesh for the block defined in 22_simple experiment.



4

intra

0

1

21

126



2. modify the run.py



stim = ["-num_stim", 1,

"-stimulus[0].vtx_file", "path/to/stim.vtx"]



Best,

by (12.1k points)
selected

You can find an example how to use the vtx file here: https://opencarp.org/q2a/804/prescribed-epicardial-potential?show=808#a808

In general it's a good idea to search the Q2A for related questions.
by (270 points)
Thank you so much! It turns out that my IntraTags leave out related regions. I fixed the bug by adding IntraTags. vtx file itself is not a problem.

Best,
by (380 points)
Could you be more specific on how did you fixed this issue? I am having a similar problem and cannot really find the problem. Thank you.