topic Re: Second Push modifier doesn't undo the First one in 3ds Max Modeling Forum

Second Push modifier doesn't undo the First one

Anonymous — Fri, 25 Sep 2015 04:08:36 GMT

Could someone help me understand this strange behavior?

1) Create box A
2) Convert to editable poly, select all the edges -> chamfer to give it a chamfer on all 12 segments.
3) apply standard Push modifier.
4) apply negative amount, until mesh starts to self-intersect
6) apply a second standard Push on top and apply the positive amount. All working.

1) Create box B
2) convert to editable poly, select all edges -> chamfer to give it a chamfer.
2.5) select all the faces -> tesselate

3) apply standard Push modifier.
4) apply negative amount, until mesh starts to self-intersect
6) apply standard Push on top and apply the positive amount. The model pushes out in some unpredictable way, not resembling the original object

Why is it so? How to prevent 3ds max from altering (I assume that's what it does) the normals.

What makes it even more strange is that Edit Normals modifier actually shows no difference between when a first push modifier is applied and after the second one is stuck on top.

Thank you!

Re: Second Push modifier doesn't undo the First one

Anonymous — Sat, 26 Sep 2015 10:15:19 GMT

@Anonymous wrote:

The model pushes out in some unpredictable way, not resembling the original object

Why is it so?

That is perfectly normal, expected behaviour, that is how the modifier stack works. Each modifer takes the mesh as it finds it, as if that were the original object.

For example if you had a long cylinder, with height segments, apply a bend of 90deg, then apply another bend of -90deg, it will not straighten it, but bend the bent mesh to create a further distortion.

Re: Second Push modifier doesn't undo the First one

Anonymous — Sat, 26 Sep 2015 22:04:08 GMT

Thank you!

Could you please clarify why the first example works (box A) and the second one won't (With box B)

In the first example, I do get the original box after I apply the second push, with inverted value, but in the second - I don't 😞

Re: Second Push modifier doesn't undo the First one

Anonymous — Sat, 26 Sep 2015 22:08:04 GMT

What I mean is, if we stick the edit normals modifier, we see that the normals (along which the push extrudes the vertices) hasn't been altered, since the push only offsets the vertex position along it.

But for some strange reason, if we stick the second push modifier, which works on exactly the same (unaltered normals), we can't "unwind" the model back into its original look as if the normals were tampered.

Thank you very much!

Re: Second Push modifier doesn't undo the First one

Anonymous — Sat, 26 Sep 2015 22:14:13 GMT

Nevermind about the other questions, indeed, the normals are tampered with after the first push modifier. So the 2nd one indeed will consider the new normals. Sigh ...Is there a way to keep original normals, and prohibit 3ds max to re-calculate them?

Re: Second Push modifier doesn't undo the First one

Anonymous — Mon, 28 Sep 2015 12:42:00 GMT

The normals of a vertex are an everage of the faces it is a corner of. When push is applied other vertices, going off on their own normal will affect the normal of a face, which in turn may the normal of all vertices on that face. Seems like you worked that out.

@Anonymous wrote:

Is there a way to keep original normals, and prohibit 3ds max to re-calculate them?

Don't use a second Push.

I could be missing something in what you are trying to acheive, but I don't understand why you want a second push countering the first one. A single push with a lesser value would give the desired result.