The issue of controlling the orientation of eco system instances came up in previous threads. I have posted before a way to orient instances using  greyscale bitmaps. [ http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3486249](http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3486249) The bitmap can contain several sections each with one specific grey value, or a grey gradient.  ( I also have a way to orient instances in a circle using math functions, without a bitmap, but I havnt posted that yet) In this thread I'm describing a way to orient instances using two helper markers and a metanode I developed. (download the attached file and rename it to remove the '.txt' extension. ) As you can see in the image(next post, as I can only attach 1 file at a time) – the instances (the  simple little  houses) are oriented in the same direction as the line between the red and blue markers. You could of course just type in the number (between -1 and 1) corresponding to the angle you want, but I think it's easier to  just 'point' to the right direction than to remember the right number to put in, and it will be easier to grasp the whole picture if you have more than one section. My next metanode will enable orienting the instances in an arc, with each instance pointing to the center of the arc (as defined by one marker)

I envisage using these two metanodes to orient items along a more complex route too – houses along the pavements, cars on the roads, sheep along a path...
You'll need to divide the path into straight and curved sections each with their own markers.
(Maybe possible to automate using python)

So this is an outline of how to use this meta node: (Material editor screen capture in the next post)

1.Chose the top view for easy  viewing and positioning of the markers
2.Add two markers (I used two spheres).
3.Add your terrain or other item you want to populate.
4.Edit your material, make it an EcoSystem, add your objects in the general tab.
5.In the 'Scaling and Orientation' tab chose 'up axis only'
6.Click 'lightning' button for 'Maximum angle' so that it is driven by the function editor, click the arrow on the right to get into  the function editor.
7.In the function editor –
 (- In my example the  density is controlled by a greyscale bitmap (followed by a filter in the density tab to select only the black part). You can chose any density you like, the orientation node will apply to all instances in the layer.)

• The orientation is controlled by a meta node.  To load the meta node click on the icon at the bottom left and browse to the location of my node.To chose the markers  click on the metanode, select from the drop down menues in the 'Markers' sections (chose the 'position' property). These markers can be items in your scene, or objects you introduce just for this purpose and you can hide them from the render.

Notes about the markers:
-They only define the orientation of the instances not their position
-It doesnt matter where you put the markers in the scene, or how close they are. Imagine a line connecting the two markers, all the instances will be oriented the same way.
-The position of  the markers along the z axis (perpendicular to the area being populated) is irrelevant – it gets zeroed in the meta node. So if you move the markers up or down this axes it wont affect the orientation of the instances.

(My computer has a 'doctor' appointment today, so just in case it needs to stay there, I'm posting this now.
I still need to clean the meta-node up a bit and add some explanations for those interested in how it works, so for the moment it's locked. But you can use it and let me know how it goes)

Examples of the ecosystem instances orientation  - imagine a line between the red and blue sphere, each instance is oriented alonge a line parallel to it.

Screen capture of the material editor/Function editor. Important bits (see first post) are circled in red.

I'm sure I missed something... let me know

This has great potential, thanks for sharing it with the community (you could instead make some money selling it in C3D :-)).

Wwo, great, thanks so much Pnina!

Thanks Artur and Bruno, I hope you(and maybe some others too) will find use for it.

Here's part two - orienting eco instances on an arc. The orientation of each instance is determined by a line connecting it with a marker. You can decide if you want the instances facing the marker, facing away from the marker or  perpendicular to the line by changing the angle offset.
The setup is similar to the one I described for the previous node. See images in the next two posts.
Please ask if you have a problem.

The image shows the effect of changing the offset angle, and of moving the marker. Moving the terrain should also work.

And this is a screen capture of the function editor. Download the node in the previous post, remove the 'txt' part from the file name, and load it into the FE. Dont forget to chose the object that you want to be your marker and select an offset angle.

If you combine both nodes(each in a different layer) you should be able to orient instances in a complex path.
Note again that the placement of the instances isnt determined by these nodes, you need to control them another way, mine is a greyscale map connected to the density output node.

If you use it and/or learn something new and you let me know that will be my reward for not trying to charge for it:)

Attached Link: http://www.renderosity.com/mod/gallery/index.php?image_id=941443

Hey!, so now you can do this! :-)

That's ingenious,  ArtPearl. I'm sure this has its uses, and maybe I can tap into them once I wrap my brain around the functions. 

 Thanks. 

> Quote - Hey!, so now you can do this! :-)

I guess I can :)
and my flying fish are organized in 3 groups: alternate circles face  clockwise and anticlockwise, and those in the radial sections face the shark in the middle.

For this I have three eco layers each with a bitmap to define the density.
Telling the fish which way to face was trivial - just typing 0, 180, -90 for the angle offset.

Paloth - is it the function editor in general that you need to sort out, or this particular function? if you have specific questions perhaps I could answer.

* is it the function editor in general that you need to sort out, or this particular function?  *

The function editor is somewhat intimidating for me at this point because I've rarely used it. Your function is no more confusing than any other. I wouldn't know the difference.

Attached Link: Follow Your Dreams

An example of applying my orientation meta-nodes in a 'real' image.

Thank goodness for folk who can do this kind of stuff, and share it! you and Eonite have done amazing stuff lately, ArtPearl! :)