View Full Version : Tree Troubles or Clip Map troubles

05-09-2014, 08:55 AM
Ok gang...here's a weird one for you. I bought some pine trees - which came in obj format.
When I brought them into modeler they have transprency for the needles. I rendered them out - they look great. I move the transparency layer to a clip map to save render time- and while they render much faster - they look terrible. WTF over!?????\

The transparency and clip map used the same image, same settings. Originally they were tiffs and I tried them as png's. Absolutely the same results.

Please see attached for a side by side comparison (including render times). If it's something stupid I can certainly live with that - just let me know what button to check. I've been loooking for the NICE TREE RENDER button for a while now - just haven't found it yet! I'm using 11.62 for Windows.

05-09-2014, 09:53 AM
Clips can't be anti-aliased for one. Second they allow for no "steps" in gradation. It's either ON or OFF. Black or White. So any feathering in the leaf images will be lost. Any transparency in the leaf image will be lost. This on/off nature is why clip maps are so fast. More a legacy feature for back when we didn't have the cpu power to render such things properly.

05-09-2014, 09:59 AM
Actually I like how the clip map version looks much better than the other one. But it does look too dark for some reason.

05-09-2014, 01:52 PM
Mr_Q - the image I'm using to clip and/or make transpent is 100% black and white - no grey. I can live with any anti-aliasing issues as these trees are meant to be in a forest of trees - no close in camera work.

Danner - I agree that the clipped version is waaaaay too dark. I just don't "get" how that can be. Or for that matter how to fix it!

05-09-2014, 04:38 PM
Displayed render times are the same?

When moving trees I exported from Vue, moving the map from Trans to Clip showed no visual difference; at least at a distance. Where'd you purchase the trees?

Is the Trans map a 1-bit image or greyscale?
Is the map used on the Translucency, Specular, Diffuse or Reflective channels?
What are the values of each of those channels if non-zero and does changing them produce a more pleasing result?

05-10-2014, 08:02 AM
Spherical - Wow! Amazing brain fart on my render time image. Geez...the clip map version render time should have been 19 seconds. Sorry about that - D'oh!

I got the trees here [URL="http://www.turbosquid.com/3d-models/3d-forest-trees---pines-model/632750"]
obj format, the original transparency map was an 8 bit RGB tiff. I stripped put all the other maps (spec, vertex normal maps etc). All there is now is color, transparency (or clip) and bump. I converted the clip map image to grey scale 8 bit jpg to see if that did anything. Nope same render with things black.

The one thing that did work - was to check unseen by radiosity in the properties panel. Which now that I consider it - would be fine as these are for a large forested area where my camera circles one specific area. Still I'd like to find out what I'm doing wrong for the next time.

05-10-2014, 05:49 PM
Why did you take the other maps out? Don't use JPG. LW doesn't work well with them. PNG, TIFF or TGA are best. I've had issues with transparency maps not going completely transparent and specular would show up on the taransparent portins of the leaf polys. JPG was the culprit, no matter what the compression level. Not being able to analyze the transparency map, I can't tell if there was information in there that required 8-bit RGB. If you're going to create a clip map from an 8-bit RGB transparency map, make it a 1-bit B/W image. Then try the 1-bit image on the transparency channel, with the clip map disabled, to note what changes. While doing this, I'd put all of the original maps back. Change one thing at a time.

05-11-2014, 08:02 AM
Spherical, I took the other maps out because I have 16,289 instances of the trees - and I figured any reduction of the original would help.
The original transparency map was a tif - same results.
I'll try the 1 bit version of the clip map. Here is a progress render of my site - using different trees just to give you an idea of the size of things. The camera flies in from here - circles the quarry as it moves closer.

05-11-2014, 04:24 PM
I took the other maps out because I have 16,289 instances of the trees - and I figured any reduction of the original would help.

The question is, not so much the render hit, if any (did you try some tests with them still in there?), but how removing them changes the look. I'd wager that with the transparency map converted to 1-bit and used as clip, combined with the original Spec, Translucent and whatever else maps put back in, that the appearance would be improved and render time not be increased all that much; while still being less than it was with the map on Transparency channel.

Here is a progress render of my site - using different trees just to give you an idea of the size of things. The camera flies in from here - circles the quarry as it moves closer.

Nice looking model. How far out from the quarry are the instances spread? Those that are far from the camera could most probably be done with a set of procedural layers. Blend the falloff of the procedurals into the instanced trees and space the instanced trees out in the other direction and you'd never see the difference. IOW, between 40% and 60% away from the camera the two methods would be blended together as a transition. The farther away, the fewer and more distributed the instances; letting more of the procedurals take over. The hybrid could be very convincing.

05-12-2014, 07:06 AM
I agree the trees might look better with all the maps. No question on that. My main bottom line question though remains the same.

With the same image map, (either the tif, png or jpg) used in either the transparency channel or as a clip map - the render comes out completely different. Much faster as a clip but much worse looking. I truely stilll don't understand why that is.

As far as your suggestion on using procedurals - that's a terrific idea. And it would allow me to extend the trees even further out. I'll give it a try once I get some caffeine in me!

05-12-2014, 04:21 PM
Hear that on the caffeine. Still not through my first espresso and surprised I'm doing so well.

OK, I'll check on a couple of projects where I use the Transparency map as Clip. They are trees that I generated from Vue, so will probably be different from what you are using. I have all of the XFrog plants, too, so will look at those. When I did this on the Vue trees, there was no difference except the render time, so it is either the model/map combination or a change in later LW versions that would cause this. The only thing that comes to mind repeatedly is that the map loses its UV coordinates when transferred to Clip and this is why the whole thing goes dark. It's there, just not properly positioned. I'll wait for the coffee t kick in before attempting.

05-12-2014, 05:26 PM
If the original was an obj all the uv maps will come into LW on top of one another as obj's use uv offset in their native program and LW doesn't (though technically you can still set it up) I suspect its the maps that are causing the problem and you need to separate them all out, this is just a guess based on what I have had to do in the past with tree and plant models that were originally obj before I converted them, not saying I'm right, just a suggestion as to where to look first

05-12-2014, 06:06 PM
Possible short answer....... Turn on Use Transparency in Radiosity settings when using just the Transparency map..... It'll look much much closer to your clip map version.
(You've already sort of done this... in reverse. You Turned off Radiosity in the clip map version to look more like the Transparency map render with Use Transparency off..... I think :hey:).

In my experience, the UV issue Spherical is speaking of has only happened to me when trying to apply the clip to a UVed object in the Node Editor. They seem to hold up in layers though. I suspect you are using layers because the silhouettes above are almost identical. Could be a scale thing though... small leaves.

All that being said:
I too like the darker image above much better. It's just a bit too dark, that's all. The first image looks flat.... like it's missing something. Radiosity on the Trans :D.

BTW nice scene! :thumbsup:

Give me a minute and I'll post a couple images to illustrate.

1) Transparency Map only. Radiosity > Use Transparency OFF.
2) Transparency Map only. Radiosity > Use Transparency ON.
3) Clip map only. Layers.
4) And, finally :D the Clip map applied in the Node Editor. What a load of......
(not sure why I felt the need to specify "UV" in the label on the last image only..... they all use the same UV and clip image)

05-13-2014, 12:31 AM
Ok, here's a series of tests from two Vue generated trees. Filenames should identify the perturbations. Times are the digits on the end:

121873 121874 121875
The third image has 50% Translucency applied, so there is some amount of extra realism. This setting isn't compatible with the map on Transparency channel, as the whole poly shows up.

121877 121878
Chose a Blooming Cherry tree to have some standard leaf patterns. Had to raise the Ray Recursion level to 26 from 6 in order to get the whole tree to be seen through all of the layered polys.

As you can see, no difference, other than the softer edges of the Transparency map version, due to AA and Grey levels.

05-13-2014, 07:38 AM
Also note, JPGs cannot be 8-bit greyscale. Even if they only contain 256 colours they are still saved to disk as 24-bit (8bpc) images. Also, don't be fooled by the on-disk size of the jpegs, what counts for LightWave is how much memory they take and a JPG takes the same amount of memory in LightWave as a PNG, TGA or 8bpc TIFF. The only difference with PNG is that if only greyscales are used only a greyscale image will be saved - an 8-bit image, rather than a 24-bit image.


05-13-2014, 07:44 AM
Ben - Oh sure NOW you tell me.... :bangwall:
After I'd converted all those tiffs to jpg's!
Well....I learn something everyday - even if it's just that I should drink more beer.....

05-13-2014, 08:18 AM
First off - thanks to all that have offered suggestions - man I appreciate it!
Here is my test renders - with settings and times.

I've also included a render that is more what I was hopeing for. This has another light added - which of course helped.
I must point out - I'm color blind - well not blind but certainly have trouble seeing greens very well - so heck maybe the straight clipped version is great! Yes....I know....maybe I should have chosen a different profession. Way too late now.

These are all rendered with a 1 bit black and white image as a clip or transparency map.


05-13-2014, 09:18 AM
Certainly the clip mapped one looks best. If you can match the tree colors to the real trees in the quarry shot (color grade in post perhaps) it will be pretty much a seamless integration.

05-13-2014, 10:35 AM
...I've also included a render that is more what I was hopeing for. This has another light added - which of course helped.

Now that's what I'm talkin' 'bout!! Lookin' good. If need be just hit it with more light.
(you might want to try an experiment with Shadows OFF for the secondary light :hey:)

I am a bit surprised that the render time for Radiosity > Use Transparency ON was shorter than OFF. :stumped:

Oh.... btw, for what it's worth. I used simple jpgs in my tests.


05-13-2014, 03:41 PM
The first image seems to have some ghosting between the leaves. Hard to tell without getting up close. As in my test renders, the clip version tends to look better when properly AA'ed. Used on the transparency channel, the edges appear too soft, as if they feather to nothing, instead of stopping; having some thickness.

In the third palm render, I set Translucency to 50%; no map. This allowed some fronds to have increased value when you can see the side opposite the light; as in the upper right center. Only added 0.1s to the render time. Because there is no map, the trunk receives the Translucency, too. This doesn't look bad, as it tends to provide some back-lighting effect, but the leaves benefit a lot.

05-13-2014, 03:56 PM
Terrific tips spherical. Thanks to everyone.