Different types of unwrapping can be applied to the same model. This is typically done with shading domains within Carrara, because the UV Editor has a feature to isolate particular geometries through this means. In Carrara 5, a new "global" shader feature has been added to allow for easy applying of textures across shading domains. In versions older than C5, a reference shader can be made to contain the applicable channels which in turns gets reference to on each individual shading domains. Obviously, the technique in Carrara 5 can save much redunent time, but the end results are ultimately the same.
Also, custom texture maps can be used on multiple and non-related models. In this tutorial, you will take the prior UV tutorial's texture maps and create UV coordornates that will be applied to the same maps. While the subject matter of the last tutorial was a metal box and this tutorial is a wooden barrel are not related, the same concept can be applied on any combination of models for a varity of reasons.
For example: if you have made a robot, you will most likely have numerous objects to texture. However, texturing each piece by itself and on its own texture maps is slow and makes it harder to maintain a consistant pallet of colors/textures/reflections/etc across each piece.
This tutorial has the following objectives:
You will need the following files to complete this tutorial:
1. Load Barrel.car. Double click on the barrel object to enter into the Vertex Modeler.
You should see the object in Figure 21.
Figure 21.
2. The shading domains on this model has not be set up for you. Lets take a moment to set them up. Select the top circle polygon and create a new shading domain called "Top_Lid". Select the bottom circle ploygon and create a new shading domain called "Bottom_Lid". Select the polygons of the upper band and create a new shading domain called "Upper_MetalBand". Select the polygons of the lower band and create a new shading domain called "Lower_MetalBand".
For the wooden boards, select the entire model and substract each shading domain's influcence from that selection. This is done by using the top menu's Selection -> Deselect By -> Shading Domain option. A pop-up will appear like in Figure 22, which asks you which domain to substract from the selection. Select Top_Lid from the list then click on "OK" button. Repeat the steps for each shading domain execept "Texture 0." After you have gotten the selection you need, create a new shading domain and name it "woodenBoards".
Figure 22.
3. With the shading domains setup, we need to apply the texture maps from the UV Tutorial #3 to this model. Do not be concerned if the metal box's texture appears on the barrel.
We will take the easiest way to apply the texture. Return to the assembly room and click on the "shader" tab. Drag and drop the "Metal Box" shader onto the black dot of the Mantipulator. NOTE: Do not drag and drop directly on the model, because this applies the shader into that specific shading domain.
If you have a Carrara 3 or 2, you can apply the texture through the texture room like you have done in the prior UV tutorials.
4. Re-enter the Vertex Modeler with the barrel selected and then enter into the UV Editor. You may automatically see an unwrapped portion of the model. In the below Figure 23, this is because of the initial creation of the model started from a cylinder object so some of the initial UV settings have the cylinder type of project already applied.
If you do not see a similar result in the UV Editor as in Figure 23, do not worry because the following steps will be the exact same and this initial UV setting will be overwritten by our later actions. Regradless of the UV lines and nodes, you should see the background image of the color channelled texture map (in this case, it is the metal box texture map which was also applied on the barrel). If you do not see the texture map then repeat step 3, because that step applies the texturemap to the model.
Figure 23.
5. Click on the "Top_Lid" option from the Shading Domain List. Have both the Wrap U and Wrap V checkboxes unchecked.
Click on the Projection tab to change the option choices. Change the type to planar, have the framed checkbox checked, click on the z-axis arrow, click on the "no split" radio button, then click on the apply button. You should see the UV Editor as in Figure 24.
Figure 24.
6. Use the UV scale tool and the move tool to postion the Top_Lid UV coordornates into the position as in Figure 25.
Figure 25.
7. Repeat steps 5 and 6 for the Bottom_Lid. When you are scaling and positioning the Bottom_Lid's UVs, try to place them on the exact top of the Top_Lid UVs.
You should remember from a prior UV Tutorial that in order to view another shading domain's UVs you will have to go back to the edit tab and check the show all checkbox. Do not be concerned with any other strange UVs that appear that isn't part of the Top_Lid and Bottom_Lid coordornates that you are setting up. In Figure 26, you will see the UV Editor with the show all checkbox checked and the top and bottom lids aligned. After you are finished aligning the Bottom_Lid UVs, uncheck the show all check box.
By overlaying the UVs on top of each other, we will be re-using the texture map for the top and bottom of the model. NOTE: If you wanted to, you could rotate the Bottom_Lid's UV before aligning them to the Top_Lid UVs so that the model will not have the Bottom_Lid's yet-to-be-painted texture maps aligned in the same direction as the Top_Lid.
Figure 26.
8. Select woodenBoards from the Shading Domain List. Have the Wrap U checkbox checked but have the Wrap V checkbox unchecked. Change to the Projection tab, select cylindrical as the type, z-axis arrow, and have the framed checkbox checked. Then click on the apply button. While the UVs are still selected, use the scale tool to shrink them and then move the UVs above the Metal Box texture as seen in Figure 27.
Figure 27.
While this may look good at first appearance, there is a problem with the UVs. Look at the highlighted polygons in Figure 28. You will notice that the preview image shows complete polygons selected, while the UV Editor only shows one row of UVs and nodes selected. The problem is that the UV Editor has placed the UV nodes on top of each other, which (if left as is) will cause of severe pixel stretching unless we manually adjust the UVs to prevent that from happening.
Figure 28.
9. Please zoom into the top left corner of the UV group we are working on. Slowly and very carefully, use the move tool and adjust the UV nodes on the top portion of the woodenBoards shading domain. Figure 29 shows my process of manually adjusting the UVs in this particular instance. Of particular note, I had to move the UV node temporarily away to get access to the node underneath it. After moving the node that was underneath, I reselected and moved the original node back into position; this is a very common practice when UV Unwrapping in Carrara. When you manually unwrap a model, keep in mind the portions of the various faces. In this case, the top, sawed through edge (across the grain) is then followed by a small amount of a with-wood grain view.
Figure 29.
After finishing the top portion of the woodenBoards UVs, your figure should look something like Figure 30.
Figure 30.
10. With the top portion done, we will work on the lower portion. Repeat Step 9 but for the lower portion of the woodenBoards UVs. Figure 31 shows my results.
Figure 31.
11. The next task to deal with is the problem with the Wrapping U polygons. The barrel was originally modeled so that one textured board is the same width as the polygon it is to be attached to. However, one wooden board wraps from one edge to the other edge, thus making for a very, very wide texture for one board. If we were to have disabled the Wrap U option (by having that box unchecked) the polygons' UVs would stretch behind all the other UVs, thus making it differcult to adjust because we would not be able to directly move this UV column from behind the others without moving all others first.
To deal with this issue, we will first click on the Display Tab. Then check the Show merge candidates and Show Split Handles checkboxes. Use the zoom tool and zoom so enough that you can see both the left and right edges of the UV set while giving you some room around the collection to work with. Use the move tool and simply select the top-most, left-most UV node. You should see something like in Figure 32.
Figure 32.
The pink dots reflect the number of polygons that use this node. In this case, the left split-node belongs to a woodenBoard, the right-split node also belongs to a woodenBoard, and the middle-split (which may appear appear the node for you and that is normal because it will move if their isn't enough top space for it) belongs to the lid ploygon. Click on drag the left-split node all the way over to an empty space on far right side of the model and to an equal distance as the other board-polygons.
In the below Figure 33, I go through the process of spliting the polygons, one-node at a time. After you move the first node, you will notice that the node where it used to belong has changed color. This color-change means that if you drag the currently split node over that other node, it will snap together again. This is used to relink the polygons on the right side of the model, but not on the left side.
Figure 33.
Continue with this process to move the entire left side over to the right side. After you are finished, you may need to zoom into the newly moved right side and tweek the UVs into a nice, neat column. At the completion of this step, your UV Editor should look like Figure 34.
Figure 34.
12. The next shading domain of the barrel to work on it the Upper_MetalBand. Double click this from the Shading Domain List. The Wrap U checkbox should be checked, but the Wrap V checkbox should not be. From the Projection tab, change the type to cylindrical, click on the z-axis arrow, then check the framed checkbox. Check on the Apply button. Your UV Editor should look like Figure 35 below.
Figure 35.
Like with the woodenBoards shading domain, we have UV nodes on top of other UV nodes. Also, the default height of this unwrapping is extreme and needs to be reduced.
To start manually unwrapping the model, we will zoom into the top left corner of this shading domain's UVs. In Figure 36, I move the UVs into a position that will be workable later on. You will notice that I had to move the first node out of the way because the order of which node was on top of the others were reversed. At the end of the animated gif, I correct the first two nodes I moved.
Figure 36.
Continued with adjusting the Upper_MetalBand's top row of nodes, then perform a similar reutine on the bottom row of nodes. At the end of this step, your unwrapping should look something like Figure 37.
Figure 37.
Select both bottom rows of nodes and move them near their above set of nodes. With the hidden nodes taken care of, we will now address the wrapping ploygon's UVs. In a similar fashion to what you've already done with the woodenBoards, go to the Display tab and activate the Show merge candidates and Show Split Handles. Zoom in-ward to the model, but leave some working room around the this shading domain's UV set. Use the split handles to detach polygons one-by-one from the left and move them to the other side of the model. When you are finished, your UV Editor should look something like Figure 38.
Figure 38.
13. We will want to place the Upper_MetalBand's UVs in relationship to the other shading domains. Click on the Edit tab if that is not already selected. Check the Show All checkbox. Use the move and rotate tools to position the UVs as seen in Figure 39.
Figure 39.
Uncheck the Show All checkbox before preceeding to step 14.
Note: If you notice a difference between the top and bottom lid's UV than in prior screenshots, it is because I had a glitch on my laptop and had to redo these shading domains.
14. Next we will UV unwrap the Lower_MetalBand. This procedure is exatly like steps 12, so if you need help with this part, refer to that step for details. When placing the unwrapped version, in a similar fashion to step 13, place the UVs as you see in Figure 40.
Figure 40.
15. You've now completed the unwrapping of the barrel. The only part now is to obtain the UV map in a bitmap image form to paint on.
To do this, click on the UV space area to deselect. Then click on the Display tab. Click on the High Resolution Texture button. Leave the default settings for point size.
You will receive a pop-up box asking you for the resolution size. I choose the 1024 option because that is the same size as the original MetalBox texture files.
Do note that when you save and resave like this, you can lose quality on the original bitmap files if you are using compressed files (Like the JPEG files that I supplied). You may consider to render only UV outline on a white background and composite that with the metal box texture in a 2D application of your choice.
Also, If you have painted your own metal box texture or choose to not use the previous texture map, you may considering using the color button instead with a background color of white.
16. The following image is my personal result from painting the wooden texture onto the barrel UVs.
Figure 41.
