Poly's Opacity Mapping Tutorial

Help and Tips on Re-Texturing existing base products on IMVU
Post Reply
User avatar
Polystyrene
Pixel Princess
Posts: 26
Joined: Sat Feb 25, 2017 6:06 pm
Location: Brisbane, Australia
Contact:

Poly's Opacity Mapping Tutorial

Post by Polystyrene » Sun Mar 05, 2017 4:31 pm

Opacity Mapping

Opacity maps are used to tell Create Mode which parts of your product you want to be seen and which you want to be invisible - it basically cuts out parts of the texture.

The Rules:
* your opacity map must be the exact same size as your texture map
* black = invisible/shows skin
* white = what is seen
* grey = sheer (darker grey = more clear; lighter grey = more solid)
* only use blending if your product has sheer/ semi see-through parts. This is because of blending clashing - if you have a blended material in front of another blended material, it often causes one of them to disappear. This is why your avi sometimes goes bald when you stand it behind windows. So it's best to leave blending turned off whenever possible.


Example 1 - Clothing

For this example, let's make a skintight tanktop. We'll derive from a skintight top, such as this one. This top covers all of the upper body and arms, so to turn it into a tank top we need to use an opacity map to cut out the parts we don't need.

First of all, here is a guide to show you which bits of the template correspond to which bits of the body. This 256x512 template is used for most skintights - it wraps around the body of the avatar.
Image

Now, for our tank top we want the "fabric" to cover these parts:
Image

So, for our opacity map we make the parts we want to see white and the parts we want to be invisible black:
Image

To put the opacity map into Create Mode, go to the Materials section in the Meshes tab. You can see where the texture and opacity maps go. Click the Edit button over the opacity map slot, choose your opacity map, then click Open. To add your texture click on the Edit button over the texture slot, choose your texture map, then click Open.
Image


Click "Apply Changes" and you'll see that your opacity map has changed the boring skintight top into a boring tank top!
Image


Example 2 - Backdrop Furniture

For this example we'll make a backdrop/enhancer. Derive from a flat plane, such as this one. This product is basically a wall, which uses an opacity map to cut parts out and turn it into something!

Say we want to create a word plane with the word "Hello!", we'll make an opacity map with the word in white and the rest black:
Image

If we want to make the word red we can use a red texture map the exact same size as the opacity map:
Image

Put in the opacity map and texture map just like in the first example. Make sure that blending is turned off by unchecking the Use blending tick box;
Image

Click "Apply Changes" and you'll get a floating "Hello!"
Image


Now say that we want to make something a bit more fancy - we will add a flame effect to the opacity map. Because we want this effect to be semi see-through, we use shades of grey:
Image

Put the new opacity map into Create Mode. And this time we want blending to be turned on, so that we can see the semi see-through parts:
Image

Click "Apply Changes" and you'll get the floating "Hello!" with a flame effect:
Image


A note about 'Blending Mode'

Under the drop down menu you can change the settings for Blending Mode. Most of the time when we need blending we will be using 'Composite' - this simply makes the texture transparent (for example, the lenses in a pair of glasses).

Image Image

The other setting is 'Additive' - Additive blending literally takes the texture and "adds" light values to it based on values in your opacity map. The more additive textures you have in front of one another, the brighter and brighter they get. This is handy for things like shafts of light. (Explanation taken from the Creator Centre)

Image Image


These are all very basic examples, but opacity map can be used to create all sorts of products, from simple shapes to complex designs - just play around and use your imagination!

I hope that my tutorial makes sense :P if you are confused or have any questions don't hesitate to ask!

You may use the opacity maps I have provided to create new products if you wish.

Have fun!
Last edited by Polystyrene on Mon Aug 28, 2017 8:55 pm, edited 3 times in total.

User avatar
Roy
Mega Pixel
Posts: 96
Joined: Sat Feb 25, 2017 4:19 pm
IMVU Homepage: http://avatars.imvu.com/Roy

Re: Poly's Opacity Mapping Tutorial

Post by Roy » Sat Mar 25, 2017 5:01 pm

That is a very....demonic hello XD


Could you maybe add something on differences between additive and composite blending?
Image

User avatar
Polystyrene
Pixel Princess
Posts: 26
Joined: Sat Feb 25, 2017 6:06 pm
Location: Brisbane, Australia
Contact:

Re: Poly's Opacity Mapping Tutorial

Post by Polystyrene » Sun Apr 23, 2017 5:41 pm

Sorry Roy, haven't checked in here for a while!

That is a good idea, I shall do so. Although I am not sure how to explain what additive does :P

User avatar
Zara
Sage Pixel
Posts: 129
Joined: Sat Feb 25, 2017 9:24 am
Location: Baix Empordà, Catalunya.
IMVU Homepage: http://avatars.imvu.com/Keodi
Contact:

Re: Poly's Opacity Mapping Tutorial

Post by Zara » Mon Apr 24, 2017 1:03 am

Polystyrene wrote:
Sun Apr 23, 2017 5:41 pm
Sorry Roy, haven't checked in here for a while!

That is a good idea, I shall do so. Although I am not sure how to explain what additive does :P
It is hard to explain because it's one of those things that is better experimented with to see if it works with the rest of the product.

Basically you don't use an opacity, just paint what you don't want to show pure black. The rest will show up depending on the strength of the lighting in the room, so it will be virtually invisible in a brightly lit room but look great in a dark room.

Additive is ideal for flames and light beams etc but only if it's dark or you can enclose them with a dark background, like flames inside a blackened fireplace for example.

I'm sure you can explain it better though with some pictures and stuff. :D
Image

Post Reply