That's interesting and also very worrying. I'm working my way through making textures that fit Misa's vanilla texture pack. I've just started on the Tinkers Construct files. I might as well play it safe and stop changing all the textures. Honestly though, how many people actually make use of frying pans, battle signs and paper weapons? I may just retexture the more commonly used components/tools and hope to avoid the limits within Optifine. Limits which are understandable, as Tinkers Construct has done something no other mod (that I'm aware) has done, making multipart/material tools. That flexability requires a lot of textures.Okay so maybe I exaggerated the amount of textures in tinker's Construct, its like 1000+, but here is a link explaining the problem with Optifine and Spax (and any other texture pack), check out the note just above the downloads. I got it from this post in which GuildMaster helped another user with the error. I doubt it will get fixed since sp614x is already working on the 1.6.x and possibly the 1.7 version of Optifine.