Creating accurate exclusion masks

Started by alpinerory, March 09, 2017, 01:16:12 PM

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Hello, first off, I like Terragen 4, good job making it.

My issue has been with creating accurate exclusion masks for my lakes and rivers. 

First question.... How do I use the "Orthographic Camera" setting, and is it what I assume, which is a way to create perfectly sized map style tiffs that I can use in Photoshop?

Another question I have is about the lake tool and water shaders.  Is it possible to use the water shaders as an exclusion mask?  Is the water shader the size and shape of the way the lake looks in my world, or does it cover that same circular region that defines the lake?

Don't worry I have more......

In the "Create Other" tab there is something called an "image writer tiff".  How do I use this?..... It has no input hookups.  Is this how I might compress my node network so to speak?  How can I make all my displacement shaded terrain modifications a part of the overarching height field?  Right now it seems like I have too much going on with all the painted shaders i've been using.  Also it seems like painted shaders are more for just small adjustments.  Is it "noobish" of me to dig entire channels in this way?

My last question is about using gradients with displacement shaders.  If I draw out the shape of the lake in photoshop, is there some sort of fill setting that fades the edges to black over whatever pixel radius you specify.  Maybe there are better adobe programs for this task, does anyone know a good way of doing this?, or maybe a good tutorial on how to go about it?

Oh yeah almost forgot.... Why can't you hook up an image shader and a painted shader to the same populations?  It would be totally radical if you could!, or, at least it seems so with my current skill set.  If it's a programmatic reason just say so.  I'm not very knowledgeable in that area.

That pretty much does it thanks for your help, i'll attach a render of my best so far, we make all the trees in xfrog and have every age class, and species found in the pacific northwest.  Would love some feedback.

I am anxiously awaiting your replies,


Trying to create a real life matrix to prepare for the machine takeover.


As it says in the Camera node documentation:
"Orthographic: If this radio button is checked the camera uses an orthographic projection. This removes the effect of perspective and can be useful for top down images, for example." So it's similar to what you describe, although it depends on what you mean by "map-style". The rendering style is the same, it's just without the effects of perspective.

The Water Shader does not have any built-in area limitations or masking functions. When applied to the Lake object, it covers the entire object, and is only limited in area due to the size setting of the Lake object itself. When applied to the terrain, a Water Shader will cover everything unless masked by another shader or otherwise limited in its distribution.

I would suggest ignoring the Image Writer Tiff node, it is an older node that is no longer used or necessary.

I'm not sure what you mean by "compress my node network", but you can save parts of your node network into Clip Files by selecting the nodes you want to save and then using the options on the File menu for clip files. Alternatively, if you mean you want to have nodes inside other nodes for purposes of organization, you can do this to a limited extent, for example by putting nodes inside of a Null, however it is a bit cumbersome and is probably most useful only when node networks get really large. Once you get used to working with internal node networks it can get easier and some people do prefer to work that way in general, but Terragen is not currently setup for the smoothest operation with this workflow. Collapsible groups, etc. would help with this.

Painted Shaders can be used for adjustments both large and small. However they are generally intended for quick and easy specific masking or other adjustment tasks. If you have the need to precisely paint a lot of masks it may be better to do so in an external image editor such as Photoshop. Painted Shaders generally use more resources than image-based masks with the same shapes, and they are also generally less precise. If they seem to be working well for your purposes and you are not encountering performance issues then feel free to continue using them. Just keep in mind the use of external image-based masks as an alternative if you encounter performance or accuracy issues.

Your Photoshop question is a bit beyond the scope of what we can provide support for here, but I can tell you there are various ways to accomplish what you're describing. One option would be to simply create your shape in Photoshop, then apply a Blur filter to it with a black background so your white shape "fades to black". The blur radius will generally be defined in pixels, which will give you something like the results you describe.

You can only hook one node at a time to any single input. However you can chain nodes together in various ways to combine the data of several nodes into one for use on the input of another node. For example if you simply feed the output of one node into the input of another, this can combine them in a simplistic way. However some nodes completely cover the results of the previous one, and you also don't get much control this way. An alternative is to use a Merge shader to merge 2 other shader nodes, and you can control how color and displacement are mixed in the settings of the Merge node, including Add, Subtract, etc. So you could, for example, subtract an image map (with a simple shape like a circle, for example) from a Painted Shader to get a circle-shaped hole in your Painted Shader. Or you could combine a Simple Shape Shader with your Image Map Shader, etc.

- Oshyan


Heh heh, must be an ortho day...I just used the ortho projection to lay and render out a road grid with real world scale road widths...very handy.
something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist


Trying to create a real life matrix to prepare for the machine takeover.