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View Full Version : Saslite - Limitations.. What are the actual values ?


Yiorgz
09-05-2002, 02:43 PM
Hi Lightwavers,

I am wondering if anyone with experience with Saslite could share some of their experiences with it.

I have built an environment to scale (including buildings) and have placed this hilly kind of area to be covered with grass in the scene.

Problem is that I have cranked up the coverage percentage figure to its maximum value and I still don't get enough grass on my hills and flat area. It's density is not thick enough.

My question
Does Saslite have some kind of polygon count or actual measurement limitations that could be causing this sparse coverage in the photo below.

http://www.users.on.net/george/images/misc/grass_problem.jpg

I have attached a ZIP file (http://www.users.on.net/george/files/grass_problem.zip) of the Scene and Hills object.

If anyone has a spare moment to help me understand what might be going on here, I would appreciate it.

Thanks

EDIT: (about half hour later)

I tried to do something (which is NOT really what I want - since it will complicate things unneccessarily)...

What I did was shrink my object in modeler to 25% of it's original size. The grass originally was about 100mm high. Scaling my object in modeler caused the grass to shrink to 25mm so I upped the percentage for the length to maintain 100mm grass height.

This is the resulting render.

http://www.users.on.net/george/images/misc/grass_prob2.jpg

Hmmm.. we have 1 of 3 hills covered in nice thick grass and the frontmost plain covered to my liking ...

My conclusion, based on observation, is that the coverage percentage is not linear with object size.

Basically if I have a 10m x 10m field of grass with 75% coverage and then I grow my field to 100m x 100m (in modeler) and keep the 75% coverage figure. The grass would not look the same.

http://www.users.on.net/george/images/misc/grass_prob3.jpg

I've shown this in the 2 renders above.

:argh:

It means that I will probably have to scale down my buildings to match the size of my environment where all the grass renders perfectly.

Does anyone with the full Sasquatch know if the coverage value goes over 250% or if this limitation is the same there ?

Thanks. :)

Rabid pitbull
09-05-2002, 03:42 PM
sas lite has many limitations one is poly count, but it just fails doesnt limit coverage like this. i have had good results but you may need to add more polys depending on count(a single poly plane isnt very good...) also make sure to have the patchiness turned down.

check for a tute on the subject at flay not long ago...

Yiorgz
09-05-2002, 03:51 PM
ya.. thanks Rabid pitbull..

Its a fairly dense mesh of polygons. Enough to give smooth detail to the hills at even varying distances.

I'm thinking, since the hills will be covered with grass (with some drooping factor) I could probably cut down on the polycount a little and see what that does. The silhouette of the hills would be broken up by the grass so I could probably go with less polygons on my mountains

As a general rule though, when I do ground planes I always subdivide them a little.

This is so that when I render, LW takes advantage of hidden polygon removal and doesn't have to render the ground under an object when you can't see it.

This is what LW does with one big polygon ground plane, and it can really slow things down when you turn on radiosity too, since it does calculations for ground that you wind up never seeing in the final render (because there's a building on top of it).

I think this problem is one of scale and the fact that it is just what it's name says - Lite !!! Its not like the real Meaty version of Sasquatch...

I guess beggers can't be choosers. Will have to put some money aside for Sasquatch.

Worley knew what they were doing when they agreed to give SasLite for free to LW7 owners. ;)

...reel that YiorgzFish in and toss it on the boat... we'll cook that one tonight..

ps. just kidding...

Tumerboy
09-05-2002, 04:10 PM
for coverage, or density or whatever, if you're at 100% and it's not enough, manually type in 150%, 200%, whatever-freakin % you want.

and then wait, a long, long, long time.

Yiorgz
09-05-2002, 04:36 PM
I think maybe it was a bit silly to ask for actual values.. but then I like to know how things work.

Thanks for the lead Rabid pitbull... found that tutorial on Flay and thought I would post it here.. It's an awesome effort.

SasLite Tutorial (http://www.nullspot.com/html/saslite.html)

Still doesn't help with my scale issue. My current coverage is at 250% which is the maximum for this variable.

From what I've read on differences between full Sasquatch and SasLite is that it has some kind of "Scaling independence (manual or automatic)" and "Landscape distance clipping".

I think these might be answers to my question.

Eugeny
09-05-2002, 09:01 PM
I think this can be useful for all Sas users.
(It's from Sasquatch manual)
P.S. from my practice i can say that braking large object (terrain) to small areas can help to cover him with grass. Also it's help to make "distance density" - u can save lot of render time using different density for near and far objects.

Per-Anders
09-05-2002, 10:05 PM
i don't know whether this is aplicable within your scene but... if you're doing stuff that far in the distance wouldnt it be just as good if you were to have a noise texture on the hills with a little fresnel lightening at the edges and perhaps the tiniest ammount of edge transparency. then just animate the noise slightly to give the impressino of movement in the wind... just a thought... might speed thigns up.

Yiorgz
09-06-2002, 04:49 AM
My god .. the people on this board are all legends.. !!!

Eugeny: Thanks for posting the Sasquatch info. I've got a funny feeling that 250% is the max in both apps.

Your words about breaking up large landscapes into smaller ones might just be what I need to solve my problem here. I'm off to try that.

mdme_sadie: Thanks also for the tip on distance. It is something I would normally do for a far away object (put less detail).

In this case though, they are hills which are only about 100m away and I will probably get close enough in the shot to see more detail on them. I'm going to do a walk around the place in one long camera shot.

Thanks for the tips folks. :)

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