今天读到一篇测验，文法实在看不太懂，求助文法高手。
句子如下:
While painting actual models, he will demonstrate how to improve skills in
making people painted in canvas seem more three-dimensional.
(手机发文一直被跳行，不好意思)
这边seem这个动词作用的主词是谁阿?
是how to…
还是people painted in canvas which seem more dimensional?
实在不太确定，有请开释，谢谢…