Only rendering a specific part but without rendering the "back" of it?

[saberlocked]

Hey guys, the title is probably quite confusing so I'll illustrate what I try to achieve.
For example, I have a G8 figure with a bra attached. I'd like to only render the bra but without seeing the parts of the bra, that wouldn't be visible if the G8 figure would be visible.

This is the render:

Now if I hide the G8 figure it only renders the bra as you'd think:

However I'd like to only see the parts of the bra that would also be visible if the female figure would be rendered.
So in this example, I'd like to have the red-ish part "removed":

Does anyone know if there's a way to tell DAZ to render it "as if" the G8 figure is visible, but without actually rendering the G8 figure, so I can achieve this result?

Thanks!

 

[Masterlordflame]

You could possibly try using a plane which will block the parts you dont want rendered

 

[DownTheDrain]

Does it have to be all done in DAZ?
Cause cutting out part of the straps of a bra in Photoshop seems like something even a noob like me could do, especially if you're rendering without a background.

 

[saberlocked]

Does it have to be all done in DAZ?
Cause cutting out part of the straps of a bra in Photoshop seems like something even a noob like me could do, especially if you're rendering without a background.

Yeah it's definitely possible to do it in PP but I was hoping to be able to do more conveniently in DAZ.
With the help of @Masterlordflame I was able to produce a result like this:



Which allows me to simply replace to black color with transparency.
But if anyone knows an even better method please let me know

 

[polywog]

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[Saki_Sliz]

Depends, do you just want to render the bra as if it was an icon?
Or do you want it to fit on the body, like some sort of overlay. If you want this, you may want to avoid making it feel cut and pasted. So you may not want to render just the bra but also include things like the shadows the bra may cast on the body, maybe even how the boobs change shape in the bra. In that case there is something you can do outside of daz (or in my case, blender).

you need your nude image and not nude image

Using Gimp (free), open the nude image, and then "open as layers" the next image or images (this only works one image at a time).
and

this does most of the work for you, and you can clean up (erasing) any extra stuff you want to if you want to make the image as small as possible
+ =
the issue is, the blank space is still data, so if you want to get the best bang per buck (if your are a hardcore dev who likes to make custom engines, just as an example) you would actually use a small image, and tag a translation vector to it so that you can fit the bra on right.

 

[osanaiko]

the issue is, the blank space is still data, so if you want to get the best bang per buck (if your are a hardcore dev who likes to make custom engines, just as an example) you would actually use a small image, and tag a translation vector to it so that you can fit the bra on right.

Technically you are right, but if the "blank areas" are all the same identical color pixels, then all modern image formats will have some sort of compression (even dumb ol' BMP or TIFF) that reduces the amount of data to encode the "blank" parts. I think so anyway....

But, in the name of science, time for an experiment.

1. Download the "just bra" image from the post above. 600x1080px. Comes as a 74,163 byte file.
2. Open in Paint.Net. Re-save as a png using the default Paint.Net settings. File size is now 98,304 bytes.
3. WTF paint.net? you made the file bigger?
4. oh well lets try cropping down to the minimum size dimensions so only the pixels that are greater than RGBA 0,0,0,0 are on the borders: File size is now 86,016 bytes
5. hmmm. so still bigger than the original image, but now with dimensions 220x225px. Something fucky is going on.
6. get another beer.
7. ah-hah! remember the evil metadata. pngcrush.com to the rescue!
8. The full size file into the machine: Original 96089 bytes | Crushed 94530 bytes | Saved 1559 bytes.
9. And the 220x225px image.: Original 85958 bytes | Crushed 84412 bytes | Saved 1546 bytes
10. Sigh and shake head sadly. Science, why have you deserted me!?!?
11. but wait, what if i CRUSH the original download image..... Original 74163 bytes | Crushed 74163 bytes | Saved 0 bytes.
12. Conclusion. Photoshop programmers know their stuff. Adobe is too STRONK. Paint.net is for poor fags noobs osanaiko.

OK, i give up. Saki Sliz, i salute you.

 

[Saki_Sliz]

6. get another beer.

Now you're doing it right XD

Yeah, png, although it is considered a type of lossless compression, it is amazing how well it does compress images. Jpeg is better, most of the time, the issue with jpeg is that it is not lossless, in noisy, detailed or small image you can see artifacting introduced by the jpeg compression. I don't know much more, so I can't say which works better with larger images, if there is a trade off at a certain image resolution that would make you use one format over another.

Actually, I wasn't using photoshop, I was using gimp, which is teh free program (it is considered number 2 second only to Photoshop itself), and if you want to use gimp but have been using photoshop, there is a version or plugin for gimp to make it look and behave like photoshop (with a few fewer tools, like the vector pen, I wish we had that, but Inkscape is a good stand-in). the file was exported from gimp, with 90% compression (default setting).

perhaps cutting or cropping may not save that much data, because some of the compression is just grouping similar parts, as I think you were trying to say.

Thanks for the salute and testing my results!

 

[polywog]

Poser (Smith Micro) or Poser Pro Game Developer
Unseen Polygon Removal
render only visible portion of clothing with alpha transparency