some specifics about populations

Started by 3Dev, September 22, 2008, 03:35:36 pm

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3Dev

I really like the sit on ground aspect of populations. i was hoping to have a population of objects to define a fence line, but ran into some issues.
the terrain is generated by a hieghtfield load file, coming out of 3dem(DEM data), for some reason when ever I ask a population to sit on this ground it instead forms a floating ring of objects around the hieghtfield.. is there a way to fix this? it does sit on randomly generated fractals.

also I had intended to use the population much like one would us an array in 3d studio max. A straight line of even placed objects, which is apparently impossible. even when one side of the population area set to 0 the objects are still slightly random placed in that axi not in a straight line. Is it possible to force force them in to an absolute line?

rcallicotte

I'll answer your first question.  The second question has been addressed by a few others in the forums and there are even TGCs to use to do what you would like to do...with some improvisation on your part.

To your first question - make sure you connect the last node of your shaders to the populations.
So this is Disney World.  Can we live here?

3Dev

hey calico, thanks for your thoughts.
the last node is connected, it didn't change the issue with the populations ring around DEM hieghtfields.

and I can't seem to find any post regarding absolute positioning of populations, if you have a key word to search or an actually link to this subject i would sure aprreciate it.

I attempted to take a screen shot of the issue, but it gives me a clipboard error, is there a work around to taking screen shots too?

rcallicotte

Then, try to connect higher up through your shader network to see if you can find the place where it settles.  There might be a reason we won't be able to find without you putting your TGD in the Support section and asking there.

Not sure about the clipboard.  The clipboard is a function of Windows.  Maybe there are other issues or perhaps you are pushing your memory to the very edge.



Quote from: 3Dev on September 22, 2008, 06:47:49 pm
hey calico, thanks for your thoughts.
the last node is connected, it didn't change the issue with the populations ring around DEM hieghtfields.
So this is Disney World.  Can we live here?

bigben

Is the bottom of the object correctly placed within the obj file?  Start a new tgd without any terrain. add the object at 0,0,0. Does it sit on the ground when rendered?

3Dev

September 23, 2008, 05:33:49 pm #5 Last Edit: September 23, 2008, 05:36:01 pm by 3Dev
ok I took a screen grab of a very small window above t2 which let me snapshot the node network and veiwport(i cropped out the rest of the interface to spare you guys my res).

this computer has 4gigs of ram so ram is not an issue.

the object loads zeroed out, its not an offset issue.

http://www.deviii.com/images/screenShot1.jpg

in the  image the yellow line on the horizon is the population ring i mentioned earlier.

this is about as simple as it can get its a hieghtfield loadfile, followed by the compute terrain node, and then a default surface shader.

i've also tried doing this with every level of the node structure being cabled to the populations with no change in result.

in other applications its common to constrain objects to a parametric surfaces, most non parametric surfaces(like a dem) can not be constrained too, so im not surprised that this hasn't worked in t2 either. that being said if anyone has an idea on how to make this work it will save me alot of time for future projects, also if there are any ideas regarding absolute positioning of populations. id still like to know.

thanks for everyone's thoughts and time so far.

dandelO

This seems to be the same problem as when you try to populate an internal TG2 sphere, planet or sun. The population lies like a flat doughnut on the ground, and sometimes, in mid-air. When you attempt a render, items that take this shape when populated just don't show up at all in the render screen.
I've never seen this with an imported object before though, if you manage to fix it, tell us how! The solution may help in a workaround for populating/positioning the TG spheres etc.
Probably not though, since you say this only happens when you populate onto an imported DEM.
Is the DEM converted to the .ter format or is it image based? If it is a .ter, take it into another app' that can open it(e.g. TG 0.9.43 - World Machine - Terrabrush - Etc...) and resave it again. Try using this newly saved .ter instead of the original one, you never know, maybe...
That's the only idea I have without having the .ter/.tgd files to examine.

bigben

Can you load the last TGD so that we can look at the other settings?   I have never had problems with populations like this before and I work mostly with TER files.

Matt

It could be caused by a position offset in the object itself. If the object is not at (0,0,0), the random rotation of instances can cause the object to sweep out an arc (because it rotates around 0,0,0). If you dragged the object away from the origin at some stage then you'd get this result. Just reset its position to (0,0,0). The reason we don't prevent this from happening is because sometimes it's a necessary feature.

The offset could also be in the object before importing it into TG.

Matt
Just because milk is white doesn't mean that clouds are made of milk.

3Dev

hey matt,

i just got an email from a buddy, who said the same thing and it started working. thanks allot that was the issue.