Retopologizing MD meshes with Boolean modifier and BSurfaces addon
( turn on English subtitles )
- Blender ( method 1 ) - best for garments made of geometrically simple, straight-edged patterns;
- Blender ( method 2 ) - best for garments made of symmetrical, geometrically complex patterns;
- Blender ( method 3 ) - universal, but is best for garments with folds/wrinkles;
- Blender ( method 4 ) - universal, but is best for people whose version of MD precedes 4.
Hello. In this tutorial, I will explain how to do manual retopology in Blender with Boolean modifier or/and BSurfaces addon.
WRITTEN TUTORIAL:
PLEASE DO NOT REPOST
Let’s start by selecting our patterns, aligning to the bottom ( RMB - Align - Bottom ) ( 1 ), distributing evenly ( RMB - Distribute - Horizontally ) ( 2 ), and moving them to the center of the grid ( 3 ).
Once done, export the mesh ( File - Export - OBJ ). Check Single Object, Unweld, Thin, Unified UV coordinates, m (for The Sims 4).
Then click on Reset 2D Arrangement ( 1 ) and export the patterns again under a different name.
Import both files in the scene. Duplicate the second one ( Shift D ) and rename it. With the renamed version selected, switch to Edit mode. Holding Ctrl, lasso-select unwanted parts ( 1 ). Use Select - Linked ( 2 ) to ensure all faces are selected, then delete them with Delete - Faces ( 3 ).
Switch to Object mode, hide everything but the duplicated mesh. Create a new plane ( Add - Mesh - Plane ) ( 1 ) and rotate it with R X 90. Activate snapping with Face snap element ( 2 ) and snap it ( G ) to the pattern mesh. Switch to Edit mode and adjust the size of the plane to fit the patterns perfectly vertically but be wider horizontally ( S X ). In Object tab change Maximum Draw Type to Wire ( 3 ).
Subdivide the plane horizontally ( Ctrl R or Tools - Subdivide ) ( 1 ). Make sure there are edges where the shape should be preserved ( the waist, for example ). Select everythig ( A ) and extrude it with E. Select the pattern mesh and extrude it, too, in the same direction. Select the plane and add Boolean modifier ( 2 ). Choose the pattern mesh as Object, set Intersect as Operation, apply. In Edit Mode delete all selected faces. If there is loose geometry left, remove it with Mesh - Clean up - Delete Loose ( 3 ).
Remove unwanted vertices by selecting one, selecting the rest with Select - Select Similar - Amount of connecting edges ( 1 ), manually deselecting a few to preserve corners and curves, deleting them with Delete - Dissolve vertices ( 2 ). Subdivide each part vertically with Ctrl R ( MMB to increase or decrease the number of edges, LMB to slide them, LMB again to finish ). Connect created edges to vertices on curved sides using Knife tool ( K ) ( 3 ). Remove extra ones with Delete - Dissolve vertices or Alt M - At first/ At last ( 4 ).
In Object Data add a UV map by hitting + ( 1 ). Then add Data transfer modifier ( 2 ) and unhide the original pattern mesh. Choose the pattern mesh as Source object, Nearest Face Interpolated in Face Data Transfer drop-down menu, UVs in Data layers to transfer, apply.
Press Shift C to move 3D cursor to the center of the scene. In Object mode go to Object - Transform - Origin to 3D cursor ( 1 ). Add Mirror modifier ( 2 ). Check U in Textures and apply.
The dress and its patterns are basically the same mesh but with vertices in different positions, meaning we can morph one into another using Shape Keys. Since the retopologized version differs from the original dress topology-wise, it cannot be used as a shape key. Fortunately, it can be bound to the original pattern mesh with Mesh Deform ( Or Surface Deform ) modifier and it will follow the transformation.
Sometimes when binding one mesh to another, you can get a “Target contains concave polygons” warning. If it happens even after using Mesh - Clean up - Split concave faces ( 1 ), apply Triangulate modifier ( 2 ) to the target mesh instead and bind again ( 3 ).
Let’s unhide the original pattern mesh and delete its duplicated version. Select the former, unfold Shape Keys in Object Data tab, press + to create Basis ( 1 ). Then select the dress mesh and Shift-select the pattern mesh again. In the special menu choose Join as Shapes ( 2 ). Click on the added option and change Value to 1 ( 3 ). As you see, the retopologized mesh followed after the original one. Select the former and apply the modifier.
Change Maximum Draw Type back to Solid or Textured. If you see the inner side of the mesh instead of outer, switch to Edit Mode, select everything ( A ) and flip normals with Mesh - Normals - Flip Normals ( 1 ). You can smooth everything by pressing Smooth button in Shading / UVs - Faces: ( 2 ) and Remove doubles in Tools ( 3 ). If needed, edit the resulting topology with Merge ( Alt M ) and Delete menus, Knife ( K ) or Connect ( J ) tools, G ( move ) with Snapping on ( Shift TAB ), etc. To ensure that there are no holes in the mesh, select everything and use Select - Select Boundary Loop ( 4 ).
Let me show you a much faster and easier way of doing manual retopology with Bsurfaces addon. Its only disadvantage is that in many cases ( example: this whole dress ) you will not be able to transfer UVs and will have to create them with Unwrap tool.
This addon is disabled by default, so start by activating it. Go to File - User Preference ( 1 ) and type in the search bar “bs” ( 2 ). Tick ( 3 ) and unfold it. As you see, it can be found in Edit Mode - Toolshelf ( 4 ). Save user settings ( 5 ).
Let’s change Maximum Draw Type to Wire and unhide the original dress to use both as references. Switch to Object Mode and create a plane with Add - Mesh - Plane. With this plane selected, switch to Edit mode, select everything and delete it with Delete - Faces. Then add Shrinkwrap modifier ( 1 ), choose the original dress as Target, set Offset to 0.001, enable Keep Above Surface and Adjust edit cage to modifier result. Go to Grease Pencil tab, set Data source to Object ( 2 ) and Stroke Placement to Surface ( 3 ). Choose Draw ( D ) or Poly ( Ctrl D ) ( 4 ) and create a few lines where you need them. In Tools tab find and unfold Bsurfaces ( 5 ). Uncheck Automatic join ( 6 ) and click on Add surface ( 7 ). Adjust Cross and Follow. Add edge loops with Ctrl R if needed. Continue drawing lines and connecting them to the surface by selecting edges with Ctrl Alt RMB and hitting Add surface button. Use Alt M menu and G with Snapping to Vertex activated to edit your results. You can also use Mesh - Vertices - Smooth vertex ( 8 ) to relax the selected area. Once done, create a new UV map in Object Data tab and transfer UVs the usual way ( or create your own ). Apply Mirror modifier with U checked and smooth everything with Smooth button in Shading / UVs tab. Join everything back, Remove doubles and change Maximum Draw Type.
The same way you can retopologize any mesh, just, as I mentioned earlier, you might have to create your own UVs from scratch.
THANK YOU FOR READING.
If you have any questions or suggestions to improve this workflow, please leave them under the video / in replies to this post / in the ask box or message them privately on tumblr / via e-mail ( [email protected] ).