why there are some crack in my mountain

i tired to make a mountain in the skybox

but it seems.........



umm i have no idea, can someone help me fix it?

 

You can put them together by selecting the displacements you want to sew together, and then pressing the "sew" button. That should fix it.

 

no, i tried it, but it have no function = =

 

What do you mean by "it has no function"? Does the option just not appear?

 

umm sorry my english grammer is shit
and i mean, i tried the "sew" but seems nothing happened

 

Displacements won't sew if the edges don't align. You'll need to make the edges the same length, or make one edge exactly half the length of the other, sharing one endpoint. Those are the only two setups that will work.

 

still not understanding....but i made a new brush with hole, seems work well

 

I'm not sure how helpful this will be as English isn't your native language, but you should refer to the Valve Developer Wiki if you haven't done so already.

 

i already read it last mouth = =
but when i tried to sewing them,it seems nothing happened

 

If nothing happened then the brushes they were originally created from aren't aligned. You have to make sure their edges match length and are touching, as the Developer Wiki states.
You can select the displacements, go to the Displacements tab and click "Destroy" to return them to brushes. Then make sure the faces are aligned and create them again.

 

From the screenshots you posted, I'm guessing the problem lies here:




These displacements don't match with the corners of the others around them, so you can't sew them. Displacements should be arranged like this, excuse my drawing:

 

wow,thanks alot

 

You're welcome!