Tree shadows on track

Alex Kyriak · Nov 20, 2010

Hi all, does anyone have any tips for creating good tree shadow effects across the track? Is it better using a standard tree Sbojects or objects (like from the GreatBritain Xpack for example), or to use invisible objects with shadow casting to create the shadow?

If anyone can post some details of their methods, techniques, setting etc, and how successful they think they are, this would be most appreciated.

I always seem to have a range of problems. Either the shadow is too soft, or it flickers.... need some advice!

Andre_1th · Nov 20, 2010

Yep, I think shadow casting planes are the best. Create a square with 2 triangels with tree textures, invisible

R Soul · Nov 20, 2010

I don't use shadows on my treewalls because they aren't close enough to the track to justify the cost to peoples' graphics cards.

For individual trees I have a special shadow object. I use the same shadow for each tree, though the object is scaled to suit each one. The shadow is based on the first tree texture because it's mostly round:

In XPacker I add a tree object, which is a few planes around a cone-shaped trunk:

and the shadow object:

I then make a complex object consisting of both of them, with the shadow not rendered and marked as a 'shadow object'.

This is what it would look like if the shadow object was rendered:

Here you can see how the shadow lines up with the widest part of the tree:

After creating the object in BTB, the 'set shadow' property is needed, with the type of shadow being 'texture'. This is the result:

But I'd only use those shadows for trees that are close enough to the track to justify it.

edit:
A method for doing static, non-flickering shadows has just occurred to me.
Make a grass texture with a shadow pasted over it. Use layer opacity to ensure the shadow isn't completely black. Load that as a background image.
Split up the terrain around the tree so that there's a circle around it, with one point in the middle. For that circle, blend the grass with the new background image:

In this example the shadow is a bit small, but other than that it looks good (for a static shadow).

Alex Kyriak · Nov 21, 2010

Soul - thanks alot for the reply mate. Awesome explanation.

This is an extract of a screenshot of Monza circuit (from the FSR2010 pack). It looks like the tree wall to the left of the image has no shadow, and some specific object shadows have been added to fall across the track. Do you think the shadows across the track are achieved in the same way as your explanation? Or is the length of the shadow shown here 'artificial', in the sense that it is not derived by the angle of the sun in relation to the shadow casting object?

R Soul · Nov 21, 2010

I looked at Brianza in scene viewer and those shadows don't move (backspace quickly changes from day to evening, evening to night etc). I looked at it in 3dSimed and it's clear that the shadows are effectively objects with a shadow texture.

Raido · Nov 21, 2010

Very good tutorial RSoul, thanks for that. Here's an idea: how about making a few "standard tree shadows" like in the Monza screenie above and then putting them into an Xpack?

Should be doable to make something like the dark "burnout patches" (stringobject) which you put on the track to make rubber stripes on the asphalt.

Alex Kyriak · Nov 22, 2010

Can anyone shed some light (sorry no pun intended...!) on the sun system in BTB? Have been fiddling with it but can't work it out. Doesn't seem to have an effect on the shadow angle too much.

Andre_1th · Nov 22, 2010

I tried it before with the btb option 'move the sunshine around' but somehow it doesnt seems to work.
So proberly you have to change the settings in yourtrackname.gdb

SkyBlendSunAngles=(-20.5, -1.0, 11.5, 25.5)
ShadowMinSunAngle=15.0
Latitude = 0 // degs from Equator (range: -90 to 90, positive is Northern Hemisphere)
NorthDirection = 245 // the direction of North in degrees (range: 0 to 359)

didnt have time to test myself.

Funny, just got the 'move the sunshine around' working , click on it and move the sun in topview

Alex Kyriak · Nov 22, 2010

Thanks Andre, I meant that when I move the sun around in top view, I can't see what difference it makes in my track...!

Andre_1th · Nov 22, 2010

Lol you did me think how to get it working, it's not only topview you can move the sun, you only can't move it in 3d view and because I work a lot in 3d view I never saw it. So basicly you can move the sun in the 3 other views. And I think you dont have to change the gdb file because after you made changes it will be saved automaticly to your gdb file. That is, when you overwrite the gdb file .
Give me 15 minutes, I create a vid wich explains I hope. brb.

there you go:

http://members.ziggo.nl/world/BTB/tuts/sun001_as.mp4

Alex Kyriak · Jan 30, 2011

Would anyone know what the best settings are for the dds file if I was making a shadow, like those described for the Brianza track above by R Soul? I have set up a tree texture with alpha channel to use as a shadow texture, to put on a wall surface, and lay the wall across the track (much like one would with a skidmark texture). It would then bet set to non drivable and allow for static shadows. Martinez, didn't you once create a post that describes the different dds settings?

ps - andre thanks for that vid man.

martinez · Jan 30, 2011

For that kind of "external" shadows - I would rather use them as objects (not walls) and with let's say 70-80% transparency to leave some terrain details below them. Somebody was saying about making objects like tree and it's shadow together - I don't know - in this case the terrain should be completely flat and even, also the tree could not be turned (since all shadows always have the same direction). So - shadows as another objects.
To get semi-transparent picture - the texture should be saved as dds DTX5 (interpolated alpha).
To make semi-transparent texture - go to the alpha channel (in Photoshop) and adjust Levels that the white part of alpha channel gets more or less gray. I don't know the best setting - you need to experiment to get results you like the best.

Just to memorize - 1 bit alpha in DTX 1 for transparency works not the best - it gives rough edges. This maybe could only be suitable if you had straight egdes (let's say - "empty" windows in a wall of a building) - DTX 3 is much better.
I have no idea why some DTX 1 textures (without transparency) have added the 1 bit alpha - it seems to do nothing, but the files are bigger. I saw this also in original textures from RBR - maybe they used something that needed this. But for BTB I don't see any use of it.

So, I know that DTX 1 gives smallest files, DTX 3 and 5 are bigger. The alfa channel makes all of them bigger. Also - the file size depends on how many mipmaps you save - the more - the bigger is the file. I thing saving "all" (which is 11 or 13 - depending on the graphic program) is a waste.

Anyway, please enlighten me - I would like to know if I'm wrong

Alex Kyriak · Jan 31, 2011

Thanks Martinez... will give it a go.... is there nothing you don't know about track building? :wink:

martinez · Feb 1, 2011

Yes, there are many things!!! One of them is - why this takes so much time?

Seriously - I would like to know more, to make my dreams come true

I'm really happy that I can help people like other people helped me a lot. And they still do

CodjaX · Feb 1, 2011

Does anyone know if the RX plugin parses vertex colour information?

If so, I could import BTB geometry into 3dsmax, bake the lighting information (e.g. Amibient occlusion / radiosity) into the vertices and then export out as a .x file.

It wouldn't create sharp track shadows, but the project i'm working on is set during a cloudy day to overcome this.

[edit] this is for Richard Burns Rally btw

Paul Minnaar · Feb 2, 2011

at the risk of ruining or derailing this very informative thread, here's my issue.

When I make my dds in Photoshop, my result is very hard edged. I've tried exporting dds1, dds3 and 5 but I'm getting the same result. How to get the export to have feathered edges ?

Alex Kyriak · Feb 2, 2011

martinez said:
For that kind of "external" shadows - I would rather use them as objects (not walls) and with let's say 70-80% transparency to leave some terrain details below them. Somebody was saying about making objects like tree and it's shadow together - I don't know - in this case the terrain should be completely flat and even, also the tree could not be turned (since all shadows always have the same direction). So - shadows as another objects.
To get semi-transparent picture - the texture should be saved as dds DTX5 (interpolated alpha).
To make semi-transparent texture - go to the alpha channel (in Photoshop) and adjust Levels that the white part of alpha channel gets more or less gray. I don't know the best setting - you need to experiment to get results you like the best.

Just to memorize - 1 bit alpha in DTX 1 for transparency works not the best - it gives rough edges. This maybe could only be suitable if you had straight egdes (let's say - "empty" windows in a wall of a building) - DTX 3 is much better.
I have no idea why some DTX 1 textures (without transparency) have added the 1 bit alpha - it seems to do nothing, but the files are bigger. I saw this also in original textures from RBR - maybe they used something that needed this. But for BTB I don't see any use of it.

So, I know that DTX 1 gives smallest files, DTX 3 and 5 are bigger. The alfa channel makes all of them bigger. Also - the file size depends on how many mipmaps you save - the more - the bigger is the file. I thing saving "all" (which is 11 or 13 - depending on the graphic program) is a waste.

Anyway, please enlighten me - I would like to know if I'm wrong

I forgot to set 'use alpha' in the Transparency drop down in materials in the Xpacker app....! No wonder my shadows weren't looking right. How do I get a darker shadow? I get the shadow to be more transparent the darker I make the image in pshop, but I still end up with these little flecks of white pixels on the edge of the shadow. What am I doing wrong? Does anyone have an example image file to show a simple tree shadow with alpha channel?

Here is my test dds file. normal on left, alpha on right.

martinez · Feb 3, 2011

This seems to be simple - make the background of the left part (the image) dark. Then you probably see light egdes, so make them dark also

The darker you make the alpha channel, the more the picture will be transparent.

Paul Minnaar · Feb 3, 2011

Using old Photoshop at home, so DDS format works, but I use CS5 64 bit PS at work. Seems this nVidia plugin does not work in CS5 64 bit ........ hmmmmmmmm, now what ?