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kccurves [2018/06/11 09:27]
piasecki
kccurves [2018/10/16 10:28] (current)
sechrest
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 Supposing you had a tree with four levels of generators: Tree, Trunk, Big Branches, and Little Branches. (**Tree #1**) What if you wanted to adjust the length of the little branches so that they are smaller at the ends of the big branches than they are at the base? Then you would merely edit the length curve without changing the parent level, as the automatic behavior of curves is to select the direct parent of the current generator. (**Tree #2**) Supposing you had a tree with four levels of generators: Tree, Trunk, Big Branches, and Little Branches. (**Tree #1**) What if you wanted to adjust the length of the little branches so that they are smaller at the ends of the big branches than they are at the base? Then you would merely edit the length curve without changing the parent level, as the automatic behavior of curves is to select the direct parent of the current generator. (**Tree #2**)
  
-But supposing ​you wanted the branches to get smaller toward the top of the tree rather than toward the end of the branches? You need to change the parent level of the curve to the Trunk rather than the Big Branches, which you do in the combobox ​in the upper left corner of the curve window. (**Tree #3**) +But suppose ​you wanted the branches to get smaller toward the top of the tree rather than toward the end of the branches? You need to change the parent level of the curve to the Trunk rather than the Big Branches, which you do in the combo box in the upper left corner of the curve window. (**Tree #3**) 
  
 What if you wanted the Little Branches to get smaller both toward the top of the tree and toward the end of the bigger branches? New in SpeedTree 8 is the ability to compute compound curves. So in the curve editor, you can adjust the curve for multiple parent levels. (**Tree #4**) What if you wanted the Little Branches to get smaller both toward the top of the tree and toward the end of the bigger branches? New in SpeedTree 8 is the ability to compute compound curves. So in the curve editor, you can adjust the curve for multiple parent levels. (**Tree #4**)
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 Profile Curves are colored light blue and affect each node in a generator the same way. This makes them work well with parent curves. Parent curves govern the group as a whole while profile curves are applied the same to each member of that group. Profile Curves are colored light blue and affect each node in a generator the same way. This makes them work well with parent curves. Parent curves govern the group as a whole while profile curves are applied the same to each member of that group.
  
-The Branch Skin Radius property provides a helpful example. If the radius of each branch remained constant, they wouldn'​t look like natural branches, but instead like logs. In real life, branches on a tree taper from base to tip. Branches are told how to taper in the SpeedTree Modeler with a profile curve. The profile curve in this case is rotated around the center of the branch with the left side of the curve corresponding to the branch base and the right side of the curve corresponding to the branch tip, as in the example below.+The Branch Skin Radius property provides a helpful example. If the radius of each branch remained constant, they wouldn'​t look like natural branches, but instead like logs. In real life, branches on a tree taper from base to tip. Branches are told how to taper in the SpeedTree Modeler with a profile curve. The profile curvein this caseis rotated around the center of the branch with the left side of the curve corresponding to the branch base and the right side of the curve corresponding to the branch tip, as in the example below.
  
 {{ :​profile_curve_example.jpg?​direct&​600 |}} {{ :​profile_curve_example.jpg?​direct&​600 |}}
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 For some properties, instead of a parent curve, there may be an orange "​distribution"​ curve. Like parent curves, distribution curves govern a group of nodes all at once. Distribution curves differ in that they control the spread of a fixed number of nodes. For some properties, instead of a parent curve, there may be an orange "​distribution"​ curve. Like parent curves, distribution curves govern a group of nodes all at once. Distribution curves differ in that they control the spread of a fixed number of nodes.
  
-If you look at the example, you can see the affect ​of a distribution curve. The curve on the bottom has been set so that the fewest level 1 branches will occur around the middle of the tree, packing most of them near the base and tip of the trunk instead of evenly, as is the case with the top curve.+If you look at the example, you can see the effect ​of a distribution curve. The curve on the bottom has been set so that the fewest level 1 branches will occur around the middle of the tree, packing most of them near the base and tip of the trunk instead of evenly, as is the case with the top curve.
  
 {{ :​distribution-curve.jpg |}} {{ :​distribution-curve.jpg |}}
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 ===== LOD Curves ===== ===== LOD Curves =====
-Dark blue curves are LOD (level of detail) curvesand only occur in LOD property groups. LOD curves govern the progression of the LOD sequence for each LOD property. In most cases, a linear progression is best suited, so that each LOD step simplifies the tree about the same amount. At times, however, it is beneficial to force a particular LOD state either earlier or later in the sequence than would occur linearly. This is achieved via LOD curves.+Dark blue curves are LOD (level of detail) curves and only occur in LOD property groups. LOD curves govern the progression of the LOD sequence for each LOD property. In most cases, a linear progression is best suited, so that each LOD step simplifies the tree about the same amount. At times, however, it is beneficial to force a particular LOD state either earlier or later in the sequence than would occur linearly. This is achieved via LOD curves.
  
-With LOD curves, the left side of the curve always corresponds to the highest LOD state (1.0), and the right side always corresponds to the lowest LOD state (0.0). This lets you have some play with the results of LOD. If your LOD step is too aggressive, move the right endpoint up a little bit to soften the effect at lower LOD's.+With LOD curves, the left side of the curve always corresponds to the highest LOD state (1.0), and the right side always corresponds to the lowest LOD state (0.0). This lets you have some play with the results of LOD. If your LOD step is too aggressive, move the right endpoint up a little bit to soften the effect at lower LODs.
  
 ==== Editing the highest LOD state with LOD curves ==== ==== Editing the highest LOD state with LOD curves ====
  
-Inversely, the left endpoint can be adjusted to alter the highest LOD state. Use this method with care, however, since these kinds of edits can easily convolute a tree setup for users who are not familiar with LOD curves.+Inversely, the left endpoint can be adjusted to alter the highest LOD state. Use this method with care, however, since these kinds of edits can easily convolute a tree set up for users who are not familiar with LOD curves.
  
 With that in mind, editing the highest LOD state does hold a great deal of power for advanced users. For instance, to reduce polygon counts, slightly lower the left endpoint of the Branch Volume Threshold Property on the highest branch level. A few of the smallest branches will be removed, but any children (such as leaves) will remain as part of the tree, since the "​phantom"​ branches they were growing from are only hidden via LOD, instead of being hard-deleted. With that in mind, editing the highest LOD state does hold a great deal of power for advanced users. For instance, to reduce polygon counts, slightly lower the left endpoint of the Branch Volume Threshold Property on the highest branch level. A few of the smallest branches will be removed, but any children (such as leaves) will remain as part of the tree, since the "​phantom"​ branches they were growing from are only hidden via LOD, instead of being hard-deleted.