Do you know UVs in modeling?

Hello everyone ！ I am a up Lord ： Basic modeling

Today is mainly about talking about and UV Some basic knowledge about .

 

One 、 exhibition UV An introduction to the

            It means to put a 3D Face of model , Flatten and expand into a corresponding 2D Coordinate image .

            So this 3D The model can be based on coordinates , Show it correctly 2D texture of material .

             Simply speaking , Is to put 3D The model is divided and processed into a plan , Then you can export it to planar software to draw maps .

 

Two 、 The basic rule

            * Try to sew large pieces of face together , Don't let UV It looks too scattered .

           ** Try to reduce 2D Image distortion , Make it meet 3D The law of the model .

         *** Place reasonably UV, Use coincident UV.

 

3、 ... and 、UV Spatial fundamentals

           * It is based on 0~1 The grid of , Smallest unit 0.1 Unit lattice of .

          One UV Mapping is to transform the three-dimensional model X、Y、Z The coordinates are converted to 2D Of UVW Space .

           ** According to the model tools and mapping tools in the software

          3D Of X The coordinates correspond to 2D Coordinate U towards , Lengthwise Y The coordinates correspond to 2D Coordinate V coordinate ,Z The coordinates correspond to W coordinate .

           *** Be careful ：

          Model flattening polygons need to be placed in UV Inside the grid , In this way, accurate texture information can be obtained in baking and rendering .

           Why UV Coordinates instead of standard projection coordinates ?

          Usually the most standard way to texture an object is to planar( Plane ),cylindrical( Cylinder ), spherical( spherical ),cubic( square box ) Coordinate projection mapping .

 

Four 、 Tangents and seams

           *  Tangent line （Tangent） The vector is actually the model space coordinate relative to U The rate of change of the value component

          And the sub tangent （Bitangent） The vector is the model space coordinate relative to V The rate of change of the value component .

           **   exhibition UV It's impossible to have no seams , however UV The joint of should be placed on the model “ hidden ” It's about .

          For example, the opening of the head should be behind the head , The thigh should be placed on the inside of the thigh and so on .

          When drawing maps, most of them use PS To draw , as for UV Joints should be BodyPaint3D To draw .

           use BodyPaint3D It's easy to handle UV Texture at seams .

           *** Be careful ：

         UV Cutting and jointing , In the organic model （ It's a model similar to biology that has no hard edges ） And hard edged models （ For example, mechanical models ）  There is a very obvious difference between .

          Because hard edged models need to cut more UV Edge joint , To reduce deformation . This also prevents errors in normals and baking .

          In addition to high modulus and smoothness , Normals also help to better shade . To ensure that it can be used in hard edged models , Cutting UV When , Some precautions need to be taken .

All right. ！ Thanks for reading , If you have any questions, you can directly find Small make up , Hopefully that helped .