topic Re: Determine where 2 extruded lines intersect in 3ds Max Programming Forum

Determine where 2 extruded lines intersect

kenc — Mon, 22 Jul 2024 20:57:30 GMT

If I have 2 walls(lines) crossing over or one of them is just touching the other, how do I determine at what point they intersect.

TIA

Ken

Re: Determine where 2 extruded lines intersect

denisT.MaxDoctor — Mon, 22 Jul 2024 23:09:17 GMT

I'd love to help you, but you're on my blacklist. I don't appreciate it when someone claims “solutions” for themselves, even if they are their own. You have eight “solutions,” all marked by you. That's not how things should work.
☝️

Re: Determine where 2 extruded lines intersect

kenc — Mon, 22 Jul 2024 23:46:37 GMT

I'm sorry. I thought that is what I was supposed to do

Re: Determine where 2 extruded lines intersect

kenc — Mon, 22 Jul 2024 23:47:21 GMT

Who marks it as a solution?

Re: Determine where 2 extruded lines intersect

kenc — Tue, 23 Jul 2024 00:57:49 GMT

@denisT.MaxDoctor I just went through our previous threads and I do see what I did wrong.

In those I accepted solution. Also noticed 2 real old threads with marked accept solution by the moderator

Re: Determine where 2 extruded lines intersect

denisT.MaxDoctor — Tue, 23 Jul 2024 03:15:35 GMT

are we talking about Bezie splines or just a simple Linear?

are we talking about 2D intersections? meaning projection

Re: Determine where 2 extruded lines intersect

kenc — Tue, 23 Jul 2024 13:06:43 GMT

@denisT.MaxDoctor I am talking about 3D linear walls. The point when one wall touches or passes through another wall.

Betreff: Determine where 2 extruded lines intersect

MartinBeh — Tue, 23 Jul 2024 13:18:15 GMT

You don't mention what you want to do once you have the intersection, but 3ds Max has the "Section" shape which computes the intersection of a mesh with a plane - does that help?

Re: Determine where 2 extruded lines intersect

kenc — Tue, 23 Jul 2024 13:40:26 GMT

@MartinBeh Where Line002 crosses Line001. I need to divide Line001 in two.

Betreff: Determine where 2 extruded lines intersect

MartinBeh — Tue, 23 Jul 2024 13:47:47 GMT

So you want to cut one plane along the line of intersection of that plane with another?

You could use a Slice modifier for this. If you want, you could remote-control the modifier's gizmo with the gizmoControl script of mine.

Or maybe the Procutter compound would be a way to do that?

Re: Determine where 2 extruded lines intersect

kenc — Tue, 23 Jul 2024 14:48:20 GMT

I better expand on what I need to do. I should have done this from the start.

I have a house full of walls. I have to check which wall intersects with what walls. I can do this with

intersects $Wall001 $Wall002.

When I find a wall that intersects another wall that wall needs to be split in two.

Here is an example

Wall005 and Wall006 intersect with Wall001. I need Wall005 to split Wall001 in two. As well as Wall006 to split it in two.

I am using MAX 2019

Re: Determine where 2 extruded lines intersect

denisT.MaxDoctor — Tue, 23 Jul 2024 17:35:23 GMT

Typically, in any architectural project, “wall line” refers to a horizontal line (floor plan), not a vertical line. In this case, we can talk about the intersection in 2D (floor), or in 3D, assuming there is another vector making the wall plane “UP”.

If you use a vertical line for the wall, you need another vector to define the wall plane... where to get it?

Re: Determine where 2 extruded lines intersect

kenc — Tue, 23 Jul 2024 18:46:57 GMT

@denisT.MaxDoctor I'm not following what you are getting at.

The walls are extruded lines and then collapsed to edit poly.

Re: Determine where 2 extruded lines intersect

denisT.MaxDoctor — Tue, 23 Jul 2024 19:46:14 GMT

@kenc wrote:
@denisT.MaxDoctor I'm not following what you are getting at.
The walls are extruded lines and then collapsed to edit poly.

Walls are usually extruded vertically. In your original pipeline, they are extruded horizontally. Maybe it makes sense to modify the pipeline first?

Re: Determine where 2 extruded lines intersect

kenc — Tue, 23 Jul 2024 19:56:17 GMT

@denisT.MaxDoctor in both my screenshots above, the walls are extruded vertically

Re: Determine where 2 extruded lines intersect

denisT.MaxDoctor — Tue, 23 Jul 2024 20:49:50 GMT

@kenc wrote:
@denisT.MaxDoctor in both my screenshots above, the walls are extruded vertically

According to this picture, the lines are vertical.

Well, uh. What do you need? Math, how do you calculate the intersecting point of two segments?

Re: Determine where 2 extruded lines intersect

denisT.MaxDoctor — Tue, 23 Jul 2024 20:56:46 GMT

fn segs_cross_point p11 p12 p21 p22 = ( a = p12 - p11 b = p22 - p21 c = p21 - p11 mag = cross a b len = (length mag) ^ 2 p0 = p11 + a * (dot (cross c b) mag)/len p1 = p21 + b * (dot (cross c a) mag)/len (p0 + p1)/2 ) delete objects --seed (timestamp()) p11 = point name:#p11 pos:(random -[100,100,0] [100,100,0]) cross:on wirecolor:green p12 = point name:#p12 pos:(random -[100,100,0] [100,100,0]) cross:on wirecolor:green p21 = point name:#p21 pos:(random -[100,100,0] [100,100,0]) cross:on wirecolor:yellow p22 = point name:#p22 pos:(random -[100,100,0] [100,100,0]) cross:on wirecolor:yellow v = segs_cross_point p11.pos p12.pos p21.pos p22.pos cp = point name:#cross pos:v cross:on wirecolor:red

Re: Determine where 2 extruded lines intersect

kenc — Wed, 24 Jul 2024 12:20:53 GMT

@denisT.MaxDoctor and how to break the wall at the intersection.

Wow, high school math. I was not expecting that.

I thought there would have been a built-in function to determine the point of intersection. Like intersects $Wall001 $Wall002. It determines if they intersect but no function to determine the point of intersection.

Betreff: Determine where 2 extruded lines intersect

MartinBeh — Wed, 24 Jul 2024 13:05:18 GMT

What intersects really does is:

Returns true if the bounding boxes of the two specified nodes overlap, or false if they do not overlap

Re: Determine where 2 extruded lines intersect

kenc — Wed, 24 Jul 2024 13:18:12 GMT

@MartinBeh What I'm saying is if script can determine an intersection occurring, then why not determine the point of intersection.