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sadkkf
05-08-2017, 11:40 AM
Hi--

Does anyone have any experience with Thomas Luft's Ivy Generator (http://graphics.uni-konstanz.de/%7Eluft/ivy_generator/?

It's a great tool for growing ivy on a mesh. I can get very nice results in VUE, but the leaf geometry in LW never uses transparency maps.

Ivy Generator only exports to OBJ format and creates a UV for the textures and as I said, they look great in VUE. By default, leaves are PNGs with transparency, but I've swapped in JPGs with separate transparency/clip maps and TGAs with alpha channels. Nothing works. I'm wondering if there's some hiccup with UVs and transparency in LW.

Any ideas?

Thanks!

Thomas Leitner
05-09-2017, 04:56 AM
....Ivy Generator only exports to OBJ format and creates a UV for the textures and as I said, they look great in VUE. By default, leaves are PNGs with transparency, but I've swapped in JPGs with separate transparency/clip maps and TGAs with alpha channels. Nothing works. I'm wondering if there's some hiccup with UVs and transparency in LW....

Hi,
if you use Layers in the Surface Editor you have to load the alpha as separate image into the Transparency Layer (there is also a way in the Image Editor to use the alpha only to separate the alpha from an image).
If you use Nodes to surface you can use an image with alpha (png, tga...) and plug the Alpha output into an "Invert" node and than into the Transparency (or Clipmap) input of your Surface.
Alternative you can use a separat alpha image as a clipmap for the object (Object Properties > Render tab > Clip map).
Clipmaps use only black and white (invisible or visible) no gray. Transparency use gray.

ciao
Thomas

Danner
05-09-2017, 05:30 AM
No hiccups that I've encountered, as long as you map the black and white image to the transparency or clip map channel using the appropiate UV. By the way I don't recommend using transparency for leaves, it will eat up the recursion limit very quickly and it doesn't block specular. Use clip maps instead.

sadkkf
05-09-2017, 05:43 AM
Hi,
if you use Layers in the Surface Editor you have to load the alpha as separate image into the Transparency Layer (there is also a way in the Image Editor to use the alpha only to separate the alpha from an image).
If you use Nodes to surface you can use an image with alpha (png, tga...) and plug the Alpha output into an "Invert" node and than into the Transparency (or Clipmap) input of your Surface.
Alternative you can use a separat alpha image as a clipmap for the object (Object Properties > Render tab > Clip map).
Clipmaps use only black and white (invisible or visible) no gray. Transparency use gray.

ciao
Thomas

Thanks, Thomas!

This is exactly what I've been doing. I haven't tried the nodes yet; I will, but I'm not sure why that would work when the layers don't.

MonroePoteet
05-10-2017, 10:15 AM
You might try cloning the image to a second instance in Image Editor, set the second instance to "Alpha Only" and use the "Alpha Only" instance in the transparency channel's layering.

mTp

Vorlath
06-13-2018, 09:33 AM
Newtek really needs to fix this. It's rather embarrassing. I'm using 2018 and it still doesn't work properly. The node has an alpha output, but it doesn't work. Invert alpha checkbox doesn't work either. There's an option to "Enable Alpha" vs "Alpha Only" and Disabled. What's the point of Enable Alpha if you can't get alpha?

oh, it's buggy. If I remove everything else from the object, it works. wow Well, the node editor works... sorta.

RPSchmidt
06-13-2018, 12:46 PM
Newtek really needs to fix this. It's rather embarrassing. I'm using 2018 and it still doesn't work properly. The node has an alpha output, but it doesn't work. Invert alpha checkbox doesn't work either. There's an option to "Enable Alpha" vs "Alpha Only" and Disabled. What's the point of Enable Alpha if you can't get alpha?

oh, it's buggy. If I remove everything else from the object, it works. wow Well, the node editor works... sorta.

I've noticed that when using images with alpha, sometimes you have to explicitly embed the alpha channel. Like, it's not enough that you have cut away portions; even when there is obvious transparency, for whatever reason, LW doesn't always pick that up. That seems to be especially true for PNGs from Photoshop.

So usually when I create a texture that needs to have alpha, I create the alpha channel explicitly and then save the image. That has worked for me.

sadkkf
06-14-2018, 07:08 AM
I've noticed that when using images with alpha, sometimes you have to explicitly embed the alpha channel. Like, it's not enough that you have cut away portions; even when there is obvious transparency, for whatever reason, LW doesn't always pick that up. That seems to be especially true for PNGs from Photoshop.

So usually when I create a texture that needs to have alpha, I create the alpha channel explicitly and then save the image. That has worked for me.

Thank you for suggesting this. I'll need to give it a try when I have some time.

jbrookes
06-14-2018, 12:05 PM
Another good one to post on the LW bug-reporting system (or via email to [email protected]). They might need a ZIP file with the scene and assets since it appears to only be an issue under certain conditions.

MSherak
06-14-2018, 01:47 PM
Hi--

Does anyone have any experience with Thomas Luft's Ivy Generator (http://graphics.uni-konstanz.de/%7Eluft/ivy_generator/?

It's a great tool for growing ivy on a mesh. I can get very nice results in VUE, but the leaf geometry in LW never uses transparency maps.

Ivy Generator only exports to OBJ format and creates a UV for the textures and as I said, they look great in VUE. By default, leaves are PNGs with transparency, but I've swapped in JPGs with separate transparency/clip maps and TGAs with alpha channels. Nothing works. I'm wondering if there's some hiccup with UVs and transparency in LW.

Any ideas?

Thanks!

After you load the Ivy object open the Image Editor. Click on the png and upper right hit the clone popup and select instance. Now select the clone of the image and the fourth popup down under alpha channel change it to Alpha Only. This is now a separated alpha channel of the image that can be used in the Clip/Transparency channels.

I used them as clipmaps really fast in the image rendered