RpTreeMaker - new version Dec 12, 2008

Al Hart

I hope to have time to get this finished soon.

We are using a concept of hexagons, rather than squares to convert the pixels to polylines. This makes a smoother shadow mask with fewer lines.

Hexagons around groups of pixels. 12 pixels (or more at lower accuracy), are used to turn on one hexagon, which is then used to create lines for the shadow border.

Since shadows do not need to be too accurate, (and renderers which process alpha-transparent images properly will create shadows directly from the image itself), we think this might work well. I am reacting to a comment Susan S. made that no automated routine can produce shadow masks as well as someone doing it by hand. She is right of course, but I am hoping we can do a better job than you get by tracing around square pixels.

Here is a sample of a RpTreeMaker tree with a "low-poly" hexagonal shadow mask. Actually I have this working for the outside edges, but not for the holes yet. If I don't have time to get the holes to work yet (It's not that hard - just takes some more programming and testing time, perhaps I will release the outside only version.)

In either case, the shadow mask will be an option with an additional option for accuracy of the tracing.

Tree maker image with hexagonal shadow mask.

sorgesu

Hi Al, this is very interesting. I'm anxious to see the result.
To be more specific as to what I said, or intended to say, is that a computer cannot do as well keeping the dual goals of "low polycount" and "satisfactory" shadow shape in mind. One or the other gets sacrificed with the automated version.

For instance we set ourselves a goal of having no more than 200 segments per tree ( more with flowers or less often repeated entourage) and a convincing shadow. We manage quite nicely but with about 20 minutes of outlining and decision making per tree.

So I am very interested in what your output is going to look like.

Al Hart

@sorgesu said:

So I am very interested in what your output is going to look like.

This is showing promise. Here is the same tree with 3 accuracy settings for the shadow masks. (I turned on view hidden geometry so you can see the edge lines which are ordinarily not visible.)

I may increase the accuracy of low just a little - to bring it to about 90 lines, and lower the accuracy of high - to bring it to about 600 lines. (The actual number of lines will depend on the complexity of the tree.)

Al Hart

Rendering with V-Ray or Podium

Are there any V-ray or Podium users out there who could test these components to see if they render properly? I have attached the SKP file. I am also planning a "rectangle" option which will make a rectangular shadow mask - if you want to keep the SketchUp models even smaller.

If you need to make modifications to make it work properly, let me know what they are and/or send me the modified .SKP file so we can try to create the components properly in the first place.

RpTreeMaker Trees with Shadow masks

sorgesu

Lovely. I do have a question though. It isn't readily apparent from the images.
At the low poly count, other solutions have had a tendencay to cut accross bits of the image. that is, it lopped off bits. With a photo it may not matter, but with a drawing, some of the nuance is in the outline and if that is removed, it really takes away from the visual.
Comment?

Al Hart

I'll keep my eye open for that.

It was my intention to not include hexagons which had only 1 or 2 pixels overlap with with the image. But I will change it to include everything. It might make the shadow slightly larger, but should still work ok.

EarthMover

Here's a quick test with Vray. I did have to add alpha mask to the trees in order to get the outline to disappear. It's odd though that the alpha map didn't seem to affect the shadow output. No worries though, as the high poly output shadow is very good as is.

Also, shadows appear the same on all trees within Podium.

Al, have you ever considered adding the ability to import a .png file into the treemaker, solely to utilize the shadow mask algorithm? This would be an indispensable tool for me as the time spent on cutting out shadow masks by hand is very tedious. It would be a handy tool for inserting a billboard and having the tool automatically generate an output with the shadow mask.

RP Treetest Vray reduced.jpg

Gaieus

@earthmover said:

Also, shadows appear the same on all trees within Podium.

I'd expect that since Podium can handle the transparent channel of the png image so its shadow is even better than that of any of the cutouts.

Nicely rendered trees!

sepo

Gaieus you are correct. .png trees render no problem in Podium

Gaieus

Actually I have found it very useful and handy with a couple of rendering engines that they support alpha channel rather than you'd need to suffer with clip masks (although they are not very hard to make from a nice alpha channels anyway)

sepo

True , clipmaps are easy to make, but when you have a lot of them in SU file it is not as easy to navigate about (of course if those are not .png)

Al Hart

@earthmover said:

Here's a quick test with Vray. I did have to add alpha mask to the trees in order to get the outline to disappear. It's odd though that the alpha map didn't seem to affect the shadow output. No worries though, as the high poly output shadow is very good as is.

Also, shadows appear the same on all trees within Podium.

Al, have you ever considered adding the ability to import a .png file into the treemaker, solely to utilize the shadow mask algorithm? This would be an indispensable tool for me as the time spent on cutting out shadow masks by hand is very tedious. It would be a handy tool for inserting a billboard and having the tool automatically generate an output with the shadow mask.

Do you add the alpha mask to the trees in SketchUp, or as a post process in V-ray.

If you add them in SketchUp, send me a model with a tree with an alpha-mask.

If you add them in V-Ray, send me a sample of the alpha-mask.

Al Hart

@earthmover said:

Here's a quick test with Vray.

I see that you placed the tree in front of a window, but it wasn't reflective.

I forgot about reflections.

Would you put one of the trees in front of a reflective window or mirror to see if we get the reflection properly?

I only put the image on one side of the tree (since they are marked as always face camera). But I may need to put a material on both sides.

Mirrored trees - IRender

EarthMover

Al, Here is the alpha map I used and were I put it. Vray runs from within sketchup, but you add the alpha map in the transparency channel from within vray.

Also, the reflections are not working in Vray.

Hope that helps.

RPTree Vray alpha example.jpg

Standard Tree (15) (copy)_clipmap.png

RP Treetest Vray_reflection.jpg

Al Hart

@earthmover said:

Al, Here is the alpha map I used and were I put it. Vray runs from within sketchup, but you add the alpha map in the transparency channel from within vray.

Also, the reflections are not working in Vray.

Hope that helps.

I will try putting the tree image on the back of the tree as well, and we can see if that helps with reflection.

If I make an alpha map, do you want me to store it on the disk somewhere, or in SketchUp somewhere?

EarthMover

I guess it would make the most sense to just output the alpha channel in the same location that the tree image is saved to. Also, there is no naming contingency in Vray, so the saved name could be anything you choose.

Al Hart

@earthmover said:

I guess it would make the most sense to just output the alpha channel in the same location that the tree image is saved to. Also, there is no naming contingency in Vray, so the saved name could be anything you choose.

The tree textures are stored initially on the disk in your temporary folder, however they would be hard to find, and not easy to get to later if you open an older model.

Here is one idea.

a. I add a hidden edge to the tree component which has a material which is the alpha channel map.

b. You can go to SketchUp / Materials / Model and right click on the "dummy" material for the alpha channel

c. After the right click, and click Export Texture image to save the image somewhere and send it to V-ray.

Al Hart

Try this model.

The tree has materials on both sides - so it should work OK in the mirror.

The tree has the alpha clipmask stored on a material on the tree itself (the material with the tree itself white), so you should be able to select the clipmask from the materials window and save the image.

clipmask material saved in SketchUp model

tree with material on both sides and clipmask

EarthMover

Al,

Reflections are working in Vray now. Alpha map also worked fine.

Thanks again

RP Treetest Vray_reflection2.jpg

juju

Al, thanks for what seems like an extremely useful app and for free on top of that!

On another note - I've tried downloading the RpTreeMaker a few times already, ZIP arrives corrupt or server is reset. I was wondering if anybody else seem to be having trouble with downloading the app?