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Sebasvideo
03-27-2014, 11:44 AM
As some of you may know, I'm trying to do a large field with hills and trees and now I need to do some very small areas where the grass has been cut completely. So I watched that tutorial from Newtek that explains how to use a weight map with the airbrush to clear some space, in that case a path, but in my case I need a small circle or a square about 2x2 meters.

My field right now is 2x2 km with 100x100 segments. The problem is that when you paint a weight map in Modeler, it's not a free paint, you can only change the weight of points, meaning you can't paint in the middle of a polygon (unless I missed something). Since each polygon in this plane is 20 meters, obviously even one vertex at 0% weight was going to be too much, so I figured I would subdivide four polygons several times to give me more points to work with. So after subdividing each polygon ends up being 2.5 meters.

After that, I airbrushed a small space at weight 0%:

121025

I saved it and went to Layout.

So now I get the small patch without grass, but unfortunately I also get this mess:

121026

Any ideas why that happens and how to fix it? Otherwise I would have to create another plane with 2000x2000 segments, and my 3930K CPU has already turned into a Commodore 64 with all the grass instancing, I don't think going from 10000 segments to 2 million will make it any better. Perhaps there is some other way to do the clear patches that is not with a weight map?

Thanks

Thomas Leitner
03-27-2014, 01:42 PM
....Perhaps there is some other way to do the clear patches that is not with a weight map?...

You can use a texture map for this. So you can paint what ever you like.

ciao
Thomas

Sebasvideo
03-27-2014, 01:46 PM
You can use a texture map for this. So you can paint what ever you like.

A texture map that is big enough to extend to a 2x2 km plane would probably slow down things a lot, wouldn't it? I mean, you're not talking about a tiled texture across the surface, but just one map with a pixel density big enough to cover the whole plane, right?

Still that wouldn't work, because I'm trying to do real grass, if I use a texture map when I'm close to the ground it will look like the grass is painted on the ground.

Thomas Leitner
03-27-2014, 02:13 PM
A texture map that is big enough to extend to a 2x2 km plane would probably slow down things a lot, wouldn't it? I mean, you're not talking about a tiled texture across the surface, but just one map with a pixel density big enough to cover the whole plane, right?

Still that wouldn't work, because I'm trying to do real grass, if I use a texture map when I'm close to the ground it will look like the grass is painted on the ground.

You can use the texture map to control where the gras (instances) grow (donīt panic, nobody will ever see this map). If you need a very high level of detail you can use a map that covers only this special area, then set Width/Hight Tile of the texture to "Edge" and scale and position it wherever you need it (best with a null as Reference Object).

ciao
Thomas

Sebasvideo
03-27-2014, 02:24 PM
That sounds good, where can I find more information on how to set this up? I googled this but I get how to use a weight map to control instances, which is what I was doing, but not how to use texture maps.

Thomas Leitner
03-27-2014, 02:47 PM
That sounds good, where can I find more information on how to set this up? I googled this but I get how to use a weight map to control instances, which is what I was doing, but not how to use texture maps.

You set up the texture map in the Instance Generator: there is a Texture button beside the "Weight" settings. Use it like any Texture Editor. The image should be a grayscale image that defines in which area the instances will grow.

ciao
Thomas

bazsa73
03-27-2014, 02:53 PM
Use the Drill tool. It's under Construct menu. You make a flat path, whatever shape you want on layer 2. On layer 1 make a gridlike plane.
Make layer 1 foreground and layer 2 as background.
-Drill
-y axis
-stencil
now you can set the weight precisely, I used this for my forest scene

Sebasvideo
03-27-2014, 03:29 PM
You set up the texture map in the Instance Generator: there is a Texture button beside the "Weight" settings. Use it like any Texture Editor. The image should be a grayscale image that defines in which area the instances will grow.

I think I may be missing something here, because I did a 10k by 10k texture in Photoshop, all white except for a black circle right at the middle. The texture is roughly 3.5 x 3.5 meters, so I assigned that when I loaded it in the instancer as a weight texture. But it doesn't do anything for the instancing, unlike when I use the weight map like in the tutorial.

Did I do anything wrong?

Sensei
03-27-2014, 05:54 PM
I think I may be missing something here, because I did a 10k by 10k texture in Photoshop, all white except for a black circle right at the middle. The texture is roughly 3.5 x 3.5 meters, so I assigned that when I loaded it in the instancer as a weight texture. But it doesn't do anything for the instancing, unlike when I use the weight map like in the tutorial.

Do you saw mine spray instances video tutorials?

Note to initial message: did you try selecting points and pressing Clear Vertex Map?

Sebasvideo
03-27-2014, 09:08 PM
Do you saw mine spray instances video tutorials?

Yea, thanks, I'm not going to spend \$300 to spray points. I tried using the native Modeler spray points tool but I ended up with too many points. I suppose I could delete some, but using Point Clone Plus with a background box with many segments was faster and easier.

Sensei
03-27-2014, 09:09 PM
I meant setting up stage in 1st video - that's where image map is used to control where are instances.
You said it doesn't work for you in post #8..

BTW, mine spraying tool is making sure that distances between points are equal - which means instances made this way do not overlap.
Which means there is much less instances needed to fill given area than any other way.
Thing you cannot do any way in LW natively AFAIK.

Sebasvideo
03-27-2014, 09:14 PM
Oh, I was going to post back and I forgot, I was able to make it work but only after I created a UV map and selected that in the weight texture.

prometheus
03-28-2014, 05:17 PM
if you do object masks, draw with the pen tool the areas you want, then use fill solid...that will fill your drawn areas with points.

Havenīt read through all these post in this thread, so this was just a tip of a hidden tool...fill solid adds small amount
of points, so click it several times to fill the area with more points.
All steps should be done in modeler.

And if you want to put points in equal spacing, you can use the quantize command, which
values you need to set, you will have to experiment with.

go to edit menu, search for fill, and it will mark fillsolid, and you can assign it to which ever menu you like

Michael

Tobian
03-29-2014, 07:20 AM
It's probably because of the ngons you created by the subdivision. Just triple or quadify them, then it should work fine.