After a frustrating experience trying to get my DAZ mermaid tail to display correctly I came to appreciate what another poster meant when they said (to paraphrase) "Carrara models transparency true to physics and poser more intuitively." Being a recent convert from Bryce, I was more of the intuitive school of thought. An hour of frustration set me right ;-) I poked around the archives for a solution to how to get carrara to treat transparency more like Poser (since that was what was needed to get my Daz tail to work right on my mermaid.) Since I didn't come across a solution in my searches, I'll post mine here although if there was a previous discussion on this, I wouldn't mind a pointer to it in case there is another way to deal with it. (I found only one previous thread but with no solution.) Anyway, my solution was to use the opacity mask in the layers channel. What worked for me was to set the topmost, root layer as all black and 100% transparent, then to add another layer that was "coverall" with color and bump as normal (in this case, the DAZ color and bump maps), transparency to value 0 (very important) and the opacity to a texture which was the DAZ transparency map. The shader is attached with the texture maps closed to get it to fit on one screen. Now my only problem is that my 100% transparent portion of my objects cast shadows, even with the caustic renderer (any suggestions?) Setting my mermaid tail to not cast shadows is okay against the mermaid's body but the tail should cast shadows against other things (in this case, a ship's hull as she is a figurehead). Any rumor of a poser to carrara plugin to speed the transition? I've heard of one for 3ds max, IIRC. Thanks, Marc

Please post a Carrara render using this method, so we can see how it works. The problem of transparent areas casting shadows might be solved by checking "Light through transparency" in Ray Tracer/Renderer settings, although ISTR that some Poser objects with detailed transparency maps (e.g. hair) may cast strange shadows when imported as facet meshes, but they would cast correct shadows when imported as vertex objects.

Also another thing to keep in mind when working with transparency in carrara is that soft shadows do not respect the transparency channel. only raytraced shadows do.

this may not be at play in your case (since we haven't seen the image yet) but i thought i'd atleast give you another possibility to investigate.

-scott

No Light Interaction When Fully Transparant is something worth checking I presume... But if the 'soft shadow' thing pixelicious mentiones holds up that is not much of help... I remember having the same problem with eyelashes, painting them in afterwards... Good luck!

Thanks both. I'll post a render tonight that uses the shader above.

In the meantime, the faerie in the link below has one of my shadow problems in it. I think this is the raytrace shadows versus soft shadows Scott mentioned. Notice the shadow of two straps over her shoulder (her dress is a strapped dress with a transparency map to remove the top).

I'm new to Cararra and don't recall a shadow/raytrace option you mention. Is that a render option? BTW the pic below does not use the opacity trick, just a texture map for transparency and the light green at dress edge is the partial transparency "glow" that seems to be well known.

My other shadow problem is more of my making and has to do with a slight gap I have between the mermaid bodice and her chest due to some morphs I applied.

Thanks,
Marc

http://www.renderosity.com/viewed.ez?galleryid=374817

Looks like my shadow from transparent objects was due to the renderer (raytracer works fine). Thanks for the pointers above.

Link below has an image rendered with Ray Tracer with a shader similar to the one above on the dress.

I've left the faerie's dress somewhat transparent to demonstrate partial transparency which I was having trouble getting right in carrara. The dress has both partial transparency and full transparency with no transition shininess. (The dress mesh is one of the Poser 5 dresses with straps over the shoulder and transparency removes the straps and scallops the hem.)

In the process also realized that poser used transparency for eyebrows and applied a similar shader to the eyebrows to get rid of my racoon look ;-). This image also changes the lights sources which cleared up many of the other funny shadows on the faerie in the earlier link.

Thanks for the help

Marc

http://www.renderosity.com/viewed.ez?galleryid=381451

Here's a picture of the DAZ mermaid tail rendered in Carrara with the transparency texture in the transparency channel on the left and with the transparency texture map in the opacity channel as in the shader at the top of this post-thread on the right. (The mermaid will be a figurehead on a ship, thus the odd pose). Marc

It seems to work o.k., but with a skin-tight transparent-edged object, you probably don't get shadows. The transparent-edge part would have to stand off from the body before shadows would be obvious. As mentioned by bijouchat IIRC, when a transparent object is within a certain distance above an opaque object in Carrara, the transparency optics start to cause strange effects that may seem like shadows (e.g. the Poser transparent eyeball material is too close to the eye to work right in Carrara).

You probably can't tell from the image above but her eyes are screwed up. I shaded them like Poser-Judy eyes but DAZ eyes are different. In the pic aboive her eyewhites are transparent ;-) (One less object in the DAZ eye IIRC). I did notice a problem with the transparent POSER eye sphere over the eye-white but that seemed to me to be more of a registration problem. That is, they didn't seem quite centered after I imported. I think that was because one was a sphere and the other was a sphere with a side cut off. One of the two programs used the sphere center as object center and the other used the actual center for the truncated sphere, I think. Sliding it over to recenter seemed to fix it. I like the DAZ eyes better, just the eye white and lens. No transparent object over the eyewhite. As for the skin tight transparent, that seems to work fine. In one incarnation, I had an offset on the skin and mermaid due to a morph not quite lining up between the two objects. In the future, I'll just mod the under-mesh after importing. Anyway, thanks for the help. The opacity trick is a big help for me when importing poser transparencies. Is this already listed somewhere? I posted my shader here for the next frustrated newbie but is this already covered on a tutorial I missed? Marc

Attached Link: http://www.renderosity.com/messages.ez?Form.ShowMessage=547974

See attached ink for Antoine Clappier's description of Carrara transparency. There are several other threads showing various shader trees using this technique, but they all devolve to Antoine's original description. There's also a reference to opacity maps at this thread: which has the link to Litst's butterfly shader tree.

Thanks!

I've done it slightly different in another thread, but boils down to the same thing. something else you need to consider... poser objects are too small for Carrara at their usual Poser scale. I have to size them up (2100 % or larger) to fix their uvs coordinates. I guess you've figured this out by now but I'm letting you know for small parts such as eyes and eyelashes, which will mess up if they are too small.

Yeah, I've run into the scale problems but more when I've tried to export an obj (to make a uv map) and reimported without doing the original export in local coordinates. Sometimes, Carrara wigs out and seems to have some sort of discrepancy between displayed size and internal size. I've had objects look okay until I try tweaking the size by a few percent and then they blow up. I really wish someone would make a poser to carrara plug-in though. I'd pay good money for that ;-) I'm getting reasonably quick at it but it is still tedious. Marc