To be able to use the effect only on the selected areas, I used the Poly select modifier, with the option Soft Selection activated.

我使用了打开软选择选项的Poly Select修改器，让它仅在被选择的区域上产生影响。

youdao

When I get the desired design, I select each part of the bridge separated and I extrude them and convert them to edit poly.

当我得到了想要的设计，我单独选出了桥梁的每一部分进行挤压操作，在编辑多边形里面进行调整。

youdao